After updating to 1.5.5, and I have tested again after updating to 1.5.6 there is a major crashing issue for Playmaker for me.
On certain scenes that I have had working for awhile, when I right click any transition on a state it causes unity to instantly crash with no report, and my mac console only give this on crash:
4/19/13 1:55:38.255 PM com.apple.launchd.peruser.502[359]: ([0x0-0xd46d46].com.unity3d.UnityEditor3.x[22974]) Exited with code: 1
For some reason if I attempt to right click the same transition that caused the crash in a different scene I get no crash. I have tested with new FSMs that I have added in the scene that is causing crashes, but it still produces the same error-less crash. I am on Mac OSX 1.8