Do not send PayPal first to anybody unless they make arrangements for their BTC to be held in escrow. Here's a list of escrowers on this forum:
https://bitcointalk.org/index.php?topic=276897.0Of course this will do nothing should you decide to charge back later. So IMHO your best course of action is just to cut out the middle man (in this case, Bitcoin) and pay the guy directly through PayPal. Problem solved.