Humm
Let's see. Fredo and I both get the same result. Hope others respond but that looks to me like problem was corrected. I guess there are two issues from my view point:

1. Why our models have two lines and yours has only one. I guess that means we are trying to skin different entities. Until that is resolved further work is fruitless. In my experience base of aerospace engineering a faring is usually a thin shell that encapsulates a payload and is the reason I thought the 0.5" thickness is correct. If I delete one of the lines what do I then try and skin? If I simply draw a cord from end to end the whole thing skins I guess I need some type of definition of the actual shell or do I miss something??
2. How many more confirmations do you need?????

I get the two lines also and is the reason I used the skinning option and get the same result as Fredo. BTW I measure 0.5 in apart and looks like by design ???
If this is not by design you may want to find the reason before going to a large project??
BTW I noted in the above post the tool triangulates and if you delete those faces are lost. Sounds like same result you are getting. My work flow is double click to get in context of the curve, select the skin tool, left click and select the total curve, select the green check and once the black is formed you need to click in space to complete the surface. Use outliner to see that a group is formed within your group and explode unless you want to keep as a nested group.

FYI for what it is worth:
Using the skinning mode and selecting the closed loop, by left to right in context select or double click on one, then selecting the green check mark skins ok each time. If I try to select one edge, right click to bring up the context menu and select extend selection to all connected I have some problems but maybe an operator error? Note: At the steep part of the curve some triangulation is none by program to get face formation.

Zacchia
I would imagine you are tried of trying to get your system to work, but there is no reason why it should work some times. Maybe if you keep a list of issues and post here when you can then you have a chance of getting the total problem fixed or better yet post your issues on one of the windows 7 support forums. The reason I say either I am not sure "sometimes" implies a SU issue or windows issue. Even though you have w64 SU still runs as a 32 bit application and is still constrained to the 4GB address memory limit and all your device drivers take a bite out of that .Stating what system you have and the graphics adapter( Much better that an intergrated chip set.) would be of interest The reason I asked about the SKU version is they have differing memory size limits. I would hope you have the one that goes to 8GB because then Su has access to much more memory then when it runs on a 32 bit system.It can use 4GB, but on a 32 bit system it can only use 2 GB even if you have 4GB memory installed.( The application and kernel split the 4GB evenly) I am neglecting paging file here.
Just some thoughts for you.

Could not find the registry issue by quick search. Will continue to look. Don't think it fits your case since SU8 was just not starting but you never know?
BTW SU M2 came out recently. SU runs as a 32 bit app on 64 bit machines. Have you checked to see if you did an automatic update recently. I don't think they rolled the version number but you can go to the extension and there is a new tab for plugin installs? If so try an correlate date on the SU file with your problem

Oops sorry I missed that. I see it is 64 bit. What SKU version do you have and did it work ok before or is it new? There have been some registery issues. Will have to see if I can find the post

Select internet options , advanced tab and at the bottom of the screen is a reset button try that and see if it helps. That sets IE to the default condition.

@tig said:

Web-dialogs made in Ruby for Sketchup use the native web-browser - in the case of a PC it's Internet-Explorer.
Have you tried downloading the latest version of IE from Microsoft and reinstalling it on your PC...
http://windows.microsoft.com/en-GB/internet-explorer/downloads/ie
You could also try reverting to an earlier version and see if that fixes the glitch...

Don't think IE9 is compatible with Windows XP. He will have to use IE8

Have you checked to see if you have a restore point before the time you have the problem. If so, try to restore there and see if that helps. If not you can go back to where you are now. If you have automatic updates turned on you may want to disable until this can be sorted out.

jeggebis
Some other ifo.
SU has a helpful component replace capability that is not often discussed here but is in the user manual.
If I select an number of components in my model, go to the component browser and select a component than select replace selected all of those selected get replace by the one from the browser. The replacement is based on the way the relative component axis of the target components are placed with respect to browser component. A component definition is invariant under move, rotate and scale operation so the replacement will even go in at the scale of the target. Using the outlier can help to select a number of components at the same time.
Just some thoughts

Exactly. Good input
If the framer you hire cannot do that with his old trusted framing square then you should not have him on the job.
Unless you are acting as an architect specifying a design vs a function will possibly give you a chance to learn the world of change orders.

John

Better get use to slope ie degrees = arctan ( 4/12) vs degrees because that is what roofer / framer will probably work with.
You would get much quicker support here if you would post what you have of your model.
Still for the life of me don't understand why you think a plugin is required?
Have you checked your codes and enforcement office yet?
You plugin could very well be NA depending on what they require vs what is modeled. They may very well have some requirements that can surprise you and you must get educated so you know. If you give the contractor a design that does not meet code , his bid is based on that and if it fails inspection guess who pays to fix??

And ditto for me

One other tid bit. If you use the section plane to make the conic it gives you the option to make the section slice a group.

According to Wikipedia iges was a DOD standard some time ago and thus many cad programs can out put it. Quick check of the Double CAD I have loaded will import and save that format so maybe you go direct form SU to iges?

Eric
Sorry did not read your post close enough. I was not " selecting everything in the problem area"

Thank you!
I'll have to spend more time with your suggestions. BTW I am using SU8 free w/o M2
My outliner ( or I should say by interruption of it )shows the same report irrespective of where I click either the problem area or not. Two components show one for the selected side and one for the mirrored side. The only difference I see is the report of the number of components in the entity info box is not consistent with the number it should be based on the radial array extent. I would never of thought to check that in any trouble shooting I would normally do. Of course the only indication I could get and reason for question was a deletion of a component in the suspect area but still have one left.

@unknownuser said:

You have two extra components on top of each other.

Remove them and your problem is solved.

New issue to me . As point of education what metric can one use to make that determination

tet42740
Some additional info for you:
I used MeshLab and and did a quadratic edge collapse decimation and was able to reduces the edges in the model by ~200,000. However Meshlab is not easy to use and looking at the model more it became apparent the basic tile model has some problems. There are a number of edges which IMO should not be there. There are some specific mathmatical relations required if you attempt to model it using the ARC tool and very small errors can cause the problems you see in that model.
If you want to correct ,create a cylinder( The OD I measured was 96.453 mm, make it just a zero thickness ( no wall thickness) I'll explain why below, extrude it up to the 250mm ht, select the top and scale down by the ratio to get the small dia you want ( I measuerd 71.190 mm for that). You can then go ahead and use the off set tool to set the 15mm thickness. The reason for waiting to this step is the scale tool will scale the thickness if you do it early. I then used the section tool to cut the truncated cylinder at one of the edges lines, make the section a group , intersect with model and delete the undesired portion. When I replaced this new tile with the ones in my posted model, which was based on what was in your orginial OP, the number of model edges reduced >= 200,000.
Just some thoughts for you

And if you read back further you will see comments about the OP approach. As usual there are more than one way to do models in SU and info to OP should not be filtered by one view point.