When this happens, usually you will have problems trying to get to Challenger Programming and User Maintenance screen.
When this happens, it means the DLSvr has stopped. To fix this:-
On Node 1, activate Shutdown from Forcefield
login to QNX shell as 'root'
# slay DLSvr (if it is still running)
# cd /usr/ares/dl
# initdb DownLoad ('y' to confirm)
# shutdown -f
Note: This clear the download buffer from the QNX Shell. This is probably cause by a previous download, so once this is done, proceed with previous download again.