Just double-checked. My 2.5-yo MBPro is a Core2Duo but the Model ID is MacBookPro2,1. I believe it needs to be at least MacBookPro4,1 to run in 64-bit mode. Doing a 'uname -m' returns 'i386' instead of 'x86_64.' Also 'About This Mac' under Sofware shows 64-bit Kernel and Extensions=No.
So I'm guessing Snow Leopard on this machine is pretty much stuck in 32-bit ice-age
Not sure what else to do to get DisplayLink drivers going. Any suggestions appreciated.