I did what you guys suggested and it worked. Thank you so much for this advice. I am back in business!

I downloaded SU2014 and went to Windows->Preferences->Extensions to put in curviloft, fredoscale, and fredolib. I found them and I downloaded them into a plugins file on my desktop. They all had the standard .zip. I then changed the .zip to .rbz. When I was done, I got a popup that said that the plugins were ready to use. But they do not appear in the extensions menu or the toolbar.
Can I fix this? If I can, how?
With SU8, the extensions worked fine!

I appreciate the attention you have given to this problem. I am thinking that I might have run out of RAM on this computer. I am posting the .skp file. Being new, I may have downloaded curviloft more than once, but I am too ignorant to know where to look for duplicates and know not is this could even be a problem.
I am able to make the surface, but when my cursor goes below the toolbar into the design zone, the program crashes. If I keep the cursor in the toolbar area, the surface remains. When I try to save it, the program crashes, and what I save is only the .skp file rails (posted below) without the surface.

These are the rails referred to in text