PXE-E53: No Boot Filename Received

This error has been round the forums a few times.  I have sccm sp1 on server 2008, pxe role is set up, wds installed.  I have checked every pre req on the Ms SCCM site and its all spot on as far as I can see.

when I F12 a client I get

PXE-E53: No boot filename received

PXE_MOF: Exiting HP PXE ROM

I have done the steps mentioned in a few posts of

1. Remove pxe role

2. Remove WDS

3. Restart

4. Add back in

5. Add boot images (both of course) to PXE DP

That didnt help

I have upgraded my WAIK to 1.1 and exported the boot images from that and imported them into SCCM

That didnt help

I found a post that said

1: Stop the WDS service.
2: Delete C:\WINDOWS\TEMP\PXEBootFiles\Windows
3: Start the WDS service.
4: Check smspxe.log again and see if <![LOG[Unable to delete directory... exists.

That didnt help

Has anyone (Wally?) got a definite answer to this pxe issue.  I didnt have any problems with my test lab and when I saw all the posts about this in the forums I assumed/hoped it was a bug that would be fixed in SP1