I admin about 30 macs in a software publishing company, and most run OS 9.2 using Quark. There had been two "flaky" G4s that caused corruption in Quark files, once or twice a week. I reinstalled the OS, checked fonts, and all the usual stuff one would do to fix a Mac. Still no luck! Then I replaced the RAM with new 256mb DIMMs and the problems disappeared for good. Just because a DIMM passes a test, doesn't mean it is trouble free. I would do as an earlier posted suggested, remove the suspected RAM and see if the problems persist. I know it is not easy to just go and purchase new RAM on a whim, but for the price of RAM today, and the frustration a bad mem stick can cause, just do it. If it is not the problem, you will have that much more memory.