I am running Windows XP on a domian from a bootcamp partition with bridged networking. My parallels installation seems to have an issue every time I boot up where it cannot obtain an IP address from out DHCP server without going into the devices menu and toggling between "default adapter" and "en1" until finally XP figures out what to do. There does not seem to be a pattern, I frequently have to switch between "default" and "en1" during the course of a normal day to maintain network connectivity. Any ideas?
Strange... You aren't changing your means of connection on the Mac side, are you? Have you tried re-installing parallels tools?