IDEA 8 on OSX 10.5.5 won't save SVN credentials

In IntelliJ 8.0 on OSX 1.5.5, I can't get the IDE to remember my SVN VCS credentials. Every time I perform any SVN operation in my projects, I am asked for my password multiple times. If I enter the password each time, eventually the operation succeeds. If I cancel any of the authentication dialogs, the operation fails. Checking the "Save credentials" button does nothing.

If I do an 'svn update' from a terminal, my credentials are properly cached.

What is going on here?