Taking image problem

Have an issue where imaging was working fine. Now all of a sudden,
cannot take image of workstation when going to ws object and
checking "take image of this on next boot" PXE starts up, grabs DHCP
address, shows where it knows what the transaction server is, etc, then
goes to ZENworks pre-boot shutting down. Never starts imaging, checked
server zenimg.xml log and it shows where it knew about the imaging job for
that particular ws object, but the error decscription says undefined
error" Booting with cd, imaging works fine. Is this an eDirectory
issue? Like I said, it all of a sudden just stopped working. Any other
logs I can check to get more descriptive error? Help !!!