State Machine Editor Blowing Up

The State Machine Editor is blowing up on me every time I try to use it. I get only a few states and transitions before it yields:

*** Fatal Error: Access Violation at 0X28746867

Module: quartus.exe

Stack Trace:

0x19810: _DllMain@12 + 0x12790 (edt_sme)

End-trace

then exits.

Is there a solution to this?

Thanks