I've installed the latest version of IntelliJ Idea Community Edition (12.0.1) and I have problems with key bindings there. I am using Ubuntu 12.04 LTS with Unity.
None of them, where a letter is involved (ctrl-a, ctrl-c, ctrl-v) are working in Idea. And they are working in all other applications.
I can copy/paste text in Idea with mouse and it shows me that key bindings for this are ctrl-c/ctrl-v, but they are just not working.
I have no idea what is the problem, so any help will be appreciated.
Usually such kind of problem is because of non-English keyboard layout being first in a list of layouts in OS settings. Try to reorder them.