I recently changed the Paypal account used as I was using my now ex-wifes, then my moms and now my sisters. I use my own account for other stuff and want to keep the forums separate. Anyway long story short this created some issues in the checkout process, right after I just got them all worked out. I apologize if your affected by this and I an working on the issue daily. I think.everything is fixed now but can only be certain once some time passes with no complaints.
In the meantime I ask you read this post and follow the instructions given there.