I'm having the exact same issue but with SubJunk's build 27.
Previous builds were fine.
EDIT : My bad, I had two instances of java.exe running. I killed both and restarted PMS. Issue resolved!!!
So Chocolate, check in the task manager for java.exe, if you have more than 1 running something is not right. Close PMS and then kill any remaining java.exe. Then restart PMS. That should solve your issue, it did for me.