I'm having same problem, even with 5.0.1 version.  I'm running it under ubuntu 12.04.m Oracle's java 1.7.0_15.  I can access definitions in my own classes, but  I can't access some definitions located in Rails sources, something that I could do with 4.5.4.  Problem is specially critical when I try to navigate from model classes.

I imported settings from 4.5.4 version.

I tried erasing .idea directory and also tried with a brand new project. Also tried using "Invalidate caches...".   I've been looking for a solution but couldn't find it.  I reverted to 4.5.4 until somebody founds a fix.  Please let me know if you can fix it.

Thanks.

Thanks for your answer.

I isolated problem looking at RubyMine logs.  It's related to using spanish accented chars in inflections initializer.  This works on RubyMine 4.5.4, but not in 5.0.x versions.

I created issue: http://youtrack.jetbrains.com/issue/RUBY-13286
RUBY-13286 Code navigation doesn't work for models if spanish accents are used in inflections.rb in RubyMine 5