.qst seems to be broken in 0.5.2. I have the same problem: when I try to log in to a zone which has quests in 0.5.2 the zone server crashes, yet copying the same quest, without editing it, over to the 0.5.1 folder and running the 0.5.1 server works fine.
So it looks like your only options are to use 0.5.1 and hope that it's fixed in 0.5.3 or switch to perl (which is what I'm doing
)