I had this on XP, what it is is windows thinking the process is dodgy, so it automatically closes it. What i did was turn of data execution prevention for silkroad.exe and sro_client.exe
I beleive it's the same for vista, however I don't know where DAP on vista is, so google it and that should fix your problem
											
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Started playing again, on CSRO now though, not ISRO (:
Hybrid  -  5x 70:70 Hybrid -  Ocean[VIP] CSRO
_EXPO_  -  7x 1H Warrior Cleric - ISRO - QUIT