OK can you play any of the "play anywhere" cartridges?
Some things I've seen that seem to cause problems include, having additional maps installed to the internal memory (should be on the SD card) having a lot of waypoints/caches loaded and having an older version of the GPS software on your machine.
Try a couple play anywhere's, if they run fine, it could be the cartridge itself. There are some out there that run well on the pocket pc and Colorado, but crash the Oregon.