Alex,
I have a similar set up and do not have persistant problems. The problems I have had are usually due to some program being skinned that doesn't want to be skinned. If you notice something in particular that is loading at the time of the crash or you get a dialogue box that gives you any clues it would be very helpful. You can create rules and tell Windowblinds not to skin a particular program. If you are certain you are running out of resources, which seems strange at 256K, check out how much stuff you have loading at start-up using MSCONFIG from the RUN command. I use Cacheman to control how memory is used and have no problem recomending it. Use the available presets first and then tweak from there. Make sure to reboot after each change. Link below, good luck...
http://www.outertech.com/
Bill