I'm not sure what causes this but I just bought the new version of Snap Deploy for use in the computer lab here. I run a Dell PowerEdge 840 with dual network cards. I don't work with the network here, only connect computers to it so I can't give you many more details. I'm the IT/support guy for a department at a large university. We use a DHCP server that requires us to register our network cards to obtain static IP address... Anyway I've been pulling my hair out trying to figure out why my machines couldn't connect/boot from PXE and just now did. If I disable one of the network cards (it doesn't matter which) it works. With both active it times out. I don't know if anyone else running dual network cards has this issue but it seems to be a significant bug, at least it was for me. Good luck.