Please refer to the following article:
Error message when you start a PXE client to connect to a WDS server on a Windows Server 2003 SP1-based computer or on a Windows Server 2008-based computer: “WdsClient: An error occurred while starting networking”
WdsClient Error – easiest way to get the driver into the image. This is either an undocumented feature or a bug – you decide.
1) Start your pxe boot (ris assumed) to capture the image from the pc with the nic problem.
2) Don’t click anything – press shift-f10 for cmd prompt
3)install your nic driver (from usb) – run setup from your nic driver package or run
drvload.exe d:\Folder\Driver.inf
4)Capture the image (you should see ris server now)
5)Drivers magically appear in the image