My site has been running with the upgrade to 1.38a since December. I've gotten orders with Pay Pal payments and everything as fine. Today I got a pay pal notification, but no order in the admin, nor did I get an email confirmation. Customer didn't get an email confirmation either, other than a receipt from Pay Pal. Pay Pal has a zen id on the transaction, so I know it came from the site.

where would I even start?