PXE - put image on workstation at next boot not working

I have recently upgraded this server to NW6.5SP6 with post SP6 patches. I
have also upgraded ZfD from 4.0.1 IR 6 to ZfD 7 w/SP1. I have also
installed HP5 for ZfD7.

Now, if in C1 I select a workstation and tell it to put an image on it on
next boot, the workstation does not see any work and continues to boot its
OS.

The wokrstations have integrated 3Com NICs.

Any ideas greatly appreciated.

Steve D.

PS

It was working before the upgrade.