I'm using lastest Intellij Idea (13.1.1) on lastest MacOS X (10.9.2)
I've installed subversion 1.8 via recently updated MacPorts and seted path to svn (/opt/local/bin/svn) in subversion properties of Idea.
However IDE shows me red baloon with "Can't use Subversion command line client: /opt/local/bin/svn".
BUT. Svn is workig and it uses this executable (because it's only way to make workspace of 1.8 format to be update).
So it seems to be a false alert, but rather annoying.