I have been getting the following error message on random machines while
PXE booting:

Heap Dispose Fail
Heap Dispose Fail
Error No Response from transaction server
Executing DNX:DEFMENU.DAT with parameters ~
Heap Dispose Fail
Heap Dispose Fail

The machines then just sit there with that message on the screen and after
awhile the 'Heap Dispose Fail' starts repeating. Even if there is no PXE
job and the machines are set to boot from the NIC this occurs and they
never boot from hard disk. It happens on the same 4 or 5 machines. I am
running ZENworks 6.5 SP1b. Was wondering if anyone else has seen this problem.