I get this error ALMOST every time I create a folder in the FeatureManager tree (not every time, I think it happens more often for more complex parts)

After this error appears the first time, it then appears whenever I try to perform  and action (create/edit a feature or sketch, save, etc).  It's not a crash, but since it forces me to restart SW, it might as well be.

Anyone else have this problem?

SW 2011 SP1.0