Hya
Consider the main log from NetBackup is in directory :
/usr/openv/netbackup/db/error
It's kept 28 days by default (can be modified through bpconfig or GUI).
You can get these informations by command : bperror -U
All the other logs are the processes logs, under personnal subdirectory in :
/usr/openv/netbackup/logs/
Hope this helped
kerk