IPConfig & DNS not working when booted BartPE from PXE/RIS

I can't get an IPCONFIG to work from BartPE when I boot if from PXE client from Microsoft Windows Server 2003+SP1 RIS server.

I am using PEBuilder 3.1.10a, server has Intel PRO1000PM & MT cards but drivers seems to work fine, using a Server 2003+SP1 as source for the build.

The basic functions of the networking seem fine, BartPE loads off the PXE server maps network drive, Ghost images to the network share fine, etc. However the new Firefox plugin is out and it would be nice to have DNS working.

If I manually run PE Network Configurator and enter a DNS Server entry manually DNS appears to work fine. However, IPCONFIG /ALL still fails.

The error from IPCONFIG /ALL is:

Windows IP Configuration

An internal error occurred: The system cannot find the file specified.

Of course IPCONFIG.EXE is located in the System32 directory like it's supposed to be.

Are there any known issues where the DNS entry will not get set automatically when BartPE boots up? Does anyone know why IPCONFIG fails when basic networking functions succeed?