Are you connected to your cable modem via ethernet? If so, the absolute easiest thing to do would be to purchase a Cable/DSL router that has multiple ports and plug your computer and your empeg both into it. Plus, you'd get additional security from the router.

If not, you'll need to either get an additional ethernet card in your computer to connect directly to the empeg or unplug your cable modem connection when communicating with the empeg. In either of those cases, you'll need to assign addresses to both the empeg and your computer (it's likely getting one automatically from your cable modem now). I'd suggest 192.168.0.1 and 192.168.0.2 (it doesn't really make any difference which is which). The netmask on both should be 255.255.255.0. After setting that up, it should work. Let us know what happens.