Since the builds have so many crashes we can't reproduce, we're going to try another approach to finding them. If you're encountering crashes in ZC or ZQuest, any help here would be appreciated.

This is for Windows only, at the moment.

Download this: http://www.mediafire.com/?7dcb1c8so5q67hn
It's a slightly modified build of 1340, plus some other stuff. It's probably better to unzip it to a new directory rather than overwrite the regular build.

Just run zlaunch-w.exe, like normal. Don't run ZC or ZQuest directly, always go through the launcher.
Whenever it crashes, just post the contents of gdb.log and let us know what you were doing at the time.

It should be safe to work on quests in this build. It may not be possible to use the same zc.sav, but you can certainly try. Just be sure to back stuff up first, as always.

This will only work if cmd.exe is in C:\Windows\System32. If you're not sure, it almost certainly is. (I did try using %WINDIR%, but that didn't seem to work.)
If it doesn't run at all, let me know and we'll try and work something out.