Thanks Thomasz, your help is much appreciated:
I activated the export function and this what I got in my ruby console:
Error: #<NoMethodError: undefined method +' for nil:NilClass> /Library/Application Support/Google SketchUp 6/SketchUp/Plugins/MatchboxPlugin/Population.rb:174:in
+'
/Library/Application Support/Google SketchUp 6/SketchUp/Plugins/su2kt.rb:156:in export_options_window' /Library/Application Support/Google SketchUp 6/SketchUp/Plugins/su2kt.rb:93:in
export'
/Library/Application Support/Google SketchUp 6/SketchUp/Plugins/su2kt.rb:2674
I have no knowledge of ruby at at all, but the message pointed at the matchbox plugin I installed not so long ago
So I closed SketchUp, removed all that had to do with 'matchbox' from my plugins-folder.
I restarted SU and..... su2kt works fine now, as it did before.
I think this ruby-interference is worth mentioning in a new tread in the 'Ruby discussions' forums (and maybe somewhere in the KT-forums. Here, it is a bit hidden.
Of course, I leave it up to you to start this 'new info'. The su2kt plugin is yours, you deserve all the credits for it and (maybe) a note from you gets more attention then one written by me. I am just a simple user of all those nice, helpfull, productive plugins.
You really helped me out with just one simple search-action. I would never have come to that on my own.
Many thanks, I can happely live on with GSU and Kerkythea !!