NDPS Error

We currently have a NW5.1 with SP1 installed and trying to run NDPS. When we were running MW5 NDPS seemed to work ok, most of the time. We are trying to set up NDPS on NT4 with sp4 128M of RAM client 4.71. We are able to see the printer and start the automatic download of the driver but during the download process we get the following spools.exe error “The instruction at 0x77e78bf4 reference memory at 0x00000000. The memory could not be read”. At this point we only have one choice, click ok andthe install exits. Also the spools.exe service has been stopped and we have to go and re-start it. Thanks for any and all help…..