I'm using ZA, but I've not seen any problems like those listed. ZA has only ever locked up when I first run a freshly patched or updated AH.
Are you running the latest ZA - I think they released another one about 2 months ago?
Cheers
Edit - Are you using RW also? I used to get lockups, freezes, etc from it
[This message has been edited by Vosper (edited 05-08-2001).]