Chris,
I've recently used the Vector CAN-AC2-PCI cards for an automotive application and have modified the Vector supplied LabView drivers, VLabLib.llb to simplify the usage from within LabView 7. Vector's technical support was very responsive in helping to overcome some of my problems dealing with the vcanap.sys driver and may be helpful for your problem. Please provide more specifics to the problem you're having.
Todd.