Using 3425 (though this seems to have been an issue with any build since the switch over to RC status) whenever I try to commit a file IDEA asks for my password (using ext:) and then always blocks when reading data from the server. Hitting cancel does nothing, hitting the red X (close button) does nothing, however the hints that come up seem to work just fine. The only solution I've found is to force quit IDEA and restart it. I haven't changed any cvs settings at all and tortoise continues to work just fine.
Not sure what other information I can provide - let me know if there is anything more I can do to assist in resolving this issue.