Netbackup process (bpfis & bpbrm) found to be hung

Hello -

We have Netbackup media server (Windows 2008) running Netbackup 7.5.0.4 and we see there are many bpfis and bpbrm in hung state after late night backup, however we dont see any backup failure but we are forced to kill this hung process.

Any suggestions?

~ Harish