Thanks! I will try do save in other place!

@tig said:

Run with the Ruby Console open: this will report progress etc...
Tell us any error messages.
If you are working with a Selection it must contain Faces...

Are no files [OBJ/MTL] or textures' folder made at all ?
Do you have permissions to make files in the destination folder etc??

I have the same problem
Everything is ok and i gave a normal name to may new file. I even ended it with .obj ...
And I have administrator rights...
that´s what loks like in the Ruby console:
OBJExporter:
C:/Users/André/Desktop/Untitled.obj
Error: #<Errno::ENOENT: No such file or directory - C:\Users\André\Desktop/Untitled.obj>
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/OBJexporter.rb:266:in initialize' C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/OBJexporter.rb:266:in new'
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/OBJexporter.rb:266:in export_start' C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/OBJexporter.rb:245:in export'
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/OBJexporter.rb:223:in initialize' C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/OBJexporter.rb:1093:in new'
C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/OBJexporter.rb:1093