PXE-E61 Nvidia boot agent error (with a twist) More options

I know there are literally dozens of threads regarding the boot agent
error "pxe-e61:media test failure check cable" however please bear
with me because this is a little different.

I actually WANT to network boot. I know usually when people post
this error it is their boot sequence set wrong or thier hard drive
that has failed. In my case the hard drive is fine and the network
cable and connection are both fine.

With the primary boot device set to Nvidia Boot Agent and the LAN
ROM enabled i am getting the media test failure error. As I said the
cable is definitely fine. Interestingly enough if I boot up with the
cable unplugged the boot agent will hang looking for the connection;
if I at this point plug the cable in the machine WILL start to

Does anyone have any idea why it would initially fail to detect the
connection or if there are any BIOS settings I might be overlooking
that need to be configured? Thanks in advance for any suggestions.