Its a memory problem, without a doubt.
Also, you may want to increase the "SIZE" resource in the Finder with ResEdit.
If you don't know how to do this, feel free to email me, or something, or post back for more information and I'll give you a step by step walkthrough.
Oh, one more thing, increase the RAM allocation to the "Appearance" Control Panel.
Need more info on that too, just ask
EDIT: Oh yeah, turn on virtual memory, to one megabyte above what you have installed.
How much RAM do you have?
It will use HD space, but improves memory management greatly.
[This message has been edited by Cipher13 (edited 03-22-2001).]