Thank you very much for the Doc...
does this only applies to the restore with Mulitplex images?
related with any specific Netbackup versions?
1)It is not related to Multiplexing.
The bprd -dontfork is the mother process for other bprd(other running child jobs) processes.
bprd -dontfork -mpxmain will act as a root and The request daemon spawns a child bprd process.
2)I have encountered this in Netbackup 7.0.1 version and I think it ll be applicable for all other versions but I dint get a chance to verify in other versions()
try with cancelling bprd jobs and start it.
But I have nt tried it
Note:when bprd is not running manual backups,user backups and restore will not work.