Thanks for your feedback!
I'm using VW 2009 SP2, on OS X 10.6.2 (Snow Leopard) As for uploading the file, i'm not sure how to do that... is there an attachment function?
The problem is still not resolved, I did find out that it occurs only on design layers. Not on a sheet layer.
Also, I'm very sure that it does not have to do with a too small/big radius. And the problem occures even when trying to fillet a simple rectangle I've just drawn. The edges do highlight as normal when hovering with the tool, and there is no error message. In fact nothing happens.
Im doubting about copying/pasting everything to a new file but that it is quite some work to set up all the viewports and layers again. Maybe it would be possible to somehow restore the file in some way?
Thanks again for your feedback
Joris