Since I found the answer to my problem I'll post it here :)
Apparently is you're running Open Trans****t 2.5.1 or lower you are
vulnerable to a DoS attack by somown sending you a UDP packet of zero
length on ****t 49152.
The answer is to upgrade to Open Trans****t 2.6 :
http://docs.info.apple.com/article.html?artnum=32075
