I've got two VMs in Parallels- one is XP which was created using Parallels and the second is Vista which is using Bootcamp. Only when I have Vista loaded, the networking on my Mac goes a bit iffy. For example, if I'm watching a move over the network using VLC, it would play for 10-15 minutes and then suddenly hang. I could see that the connection to the networked drive disappeared. I could reconnect to it and again after 1-15 minutes, same thing would happen. This would only occur if the Vista VM is running using the Bootcamp partition. Anything that I can enable/disable in Vista that might "capture" the Network card or something?
Try to use Bridged Ethernet as described in Parallels Desktop for Mac user guide from http://www.parallels.com/en/download/file/doc/Parallels_Desktop_for_Mac_User_Guide.pdf on page 157
Sorry for the delayed reply but it is already set in dridged mode as I need that to access other shares on the Network.