Hello.
I had a problem with RDoc when installing various gems (mysql, mongrel). I often got error messages of the kind "No definition for XXX". When doing a google search with that error then it seems that a lot of people do have that problem. I never read a solution (most recommend to simply suppress the generation of the documentation). But a simple "gem install rdoc-data" seems to solve the problem. I don't know why (maybe you can tell me?!), but it works.
Best regards, Kai