Hello,
One common problem is that you don't have your dip switch settings correct on your board. Check the diagram in the Configuration Utility to verify that these are correct on your pcStep-4AOL. If this is done correctly, then try to install the board on a different PC so we can determine whether there may be a problem with the board, or a confict with that particluar system.
Regards,
Andy Bell
Application Engineer
National Instruments