There was a patch that was needed for 3.1 to work right. I will try to 
get a release for 0.5.0 out with a patch for Eclipse 3.1 out as soon as 
I can, perhaps this weekend, or sometime next week...

The RDT (rubyeclipse) team is working on 0.6.0 targeted for Eclipse 3.1 
at the moment also, but I can't say we know any expected release dates.

Zach