Eureka! 
It works again. Finally I got one of the admin's to erase the compspray.rb plugin and shape bender works neatly again!
Couldnt figure it out earlier; as I don't have access to make any change in the plugin folder...
Thanks again for the help. This plugin is great!!! Its helping me so much with my architecture models!
Thanks Chris!! thanks TIG!!
Hello TIG, thanx for the feed back:
The error appears after selecting the curve. The process bar freezes at 2% or 5%
The object is a "group", the line is in the red axis and doesnt touche anything, the curve doesn't either
first time it worked perfectly 
next dqy stopped working 
the model is the simplest possible; I attach it.
Yesterday I read the first 20 pages in this forum 
I think it might be a problem with compspray.rb or maybe SketchyFFD. At the office I have no "administrator acces" to remove them, but I will ask and try to remove them as soon as possible.
Thank you.
here' the beggining of the error message:
Error: #<ArgumentError: comparison of Float with nil failed>
(eval):44:in >' (eval):44:in update'
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:533:in exploder' C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:526:in each'
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:526:in exploder' C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:244:in onLButtonUp'
Error: #<NoMethodError: undefined method /' for nil:NilClass> C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671:in draw'
(eval):44
Error: #<NoMethodError: undefined method /' for nil:NilClass> C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671:in draw'
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671
Error: #<NoMethodError: undefined method /' for nil:NilClass> C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671:in draw'
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671
I got the progressbar installed, etc
Yesterday it was working neatly!! that's what buggin me the most.
found this:
n draw' C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671 Error: #<NoMethodError: undefined method /' for nil:NilClass>
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671:in draw' C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671 Error: #<NoMethodError: undefined method /' for nil:NilClass>
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671:in `draw'
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/clf_shape_bender/clf_shape_bender.rb:671
Hello everybody!first time posting.
Yesterday I installed some ruby plugins for sketchup (8)and tried out the Chris Fullmer Shape Bender. After a while, I managed to make it work succesfully, bending the rqmp Im working at (architecture digital model). Everything fine and happy as hell.
Then, this morning, same file, same computer, doing exactly the same steps, the bender tool doest work:
I draw the figure, group it up, draw the line along red axis, same length, and the single curve. select group, open the tool,select the line,select the curve. the signs "start" "end" appear, I can change their position, but thats it! no green shape, no final bended figure.
Maybe the answer is alreqdy somewhere in the forum, but theres a lot of posts, and i have so little time, i got a delivery today and have to finish the model as soon as possible.
thanx in advance