I've been throwing this around in random threads about zone crashing, as it worked miracles for me.
If you have a SBLive based sound card, try turning off all sound (not down, off). This fixed my zoning problems, as well as the crash a few minutes after loggin in problems, as well as most of my crash sometimes when loading a bunch of new graphics problems.
After playing without sound most of the time since release, I recently purchased a SB Extigy external soundcard. I have since been able to turn the sound back on and have no major problems with zoning or crashing. I also had no problems on a different system that was using an internal Crystal-based sound chipset, but that might have been a fluke.
I have posted this to a few other people, and it has worked for them as well. I don't know if it is a good generic fix, but it certainly worked for me and a few others.
Second solution I have seen (might even be the same issue really) is that if you can reconfigure your system so that nothing is sharing an IRQ with your videocard and sound card (difficult on an acpi system sometimes) then that fixes a myriad of lockups and crashes.
Hope this helps someone.