Printing Error

I have a user that is getting the following error sporadically:

ERROR: MemoryFull
OFFENDING COMMAND: findresource

STACK:

/RelativeColorimetric.non.DefaultHalftone

THe printer prints out a page with that error and then stops. Does anyone know what would cause this error? The printer is a Xerox Phaser 3500 that is being used as a network printer and is using the PS driver.