Hi Terry,
Did you try to close the PO window after removing the fms?
Do you have any add-ons running, if yes, stop them and try again?
Whats your SAP version and PL? Did you check the same on a latest PL of version 9?
If you have checked these and still have the same issue, I think it would be best to open a ticket with SAP cause it looks like a bug.. Never seen this one before though..
Thanks,
Joseph