If anyone is trying to talk to the SP601 board via ethernet on Windows XP installed on Parallels running on a Mac OSX Leopard, here is the process I followed to get the VM to recognize the board.
Step 1) Most XP installations on Parallels is bare bone. So update XP till all the patches are installed (with windows as the OS, you never know what happens without those patches)
Step 2) In Parallels configuration for the network, choose Bridged networking with Ethernet
Step 3) In the Macintosh network preferences, allow the configuration to be DHCP. But in the advanced option, go to ethernet tab and note the Ethernet ID number. This is the MAC/physical address that is critical because the S6 chip reference design does not use the IP stack (hence no IP address), just MAC.
Step 4) Enter this Ethernet ID as the MAC address in the network adapter configuration of Parallels.
Step 5) In the Windows firewall settings, advanced option, make sure the local area connection check box is not checked. This ensures that firewall is not being applied to the ethernet port. Simply disabling the vanilla firewall settings in windows didn't take care of this.
Now simply restart the virtual machine (parallels) and the base reference design interface gui will recognize the FPGA using the Realtek network adapter.