Do you have a NetBackup Appliance?
I see that you have posted in the NetBackup forum as well, saying that you have a Linux Master server.
Have you tried to download NetBackup for VMware Administrator's Guide and go through the Troubleshooting chapter?
There are topics such as :
■ Notes on troubleshooting NetBackup for VMware
■ Beware of unsupported backup host
■ How to determine the ESX network that NetBackup used for the backup or restore
■ NetBackup logging for VMware
■ Preventing browsing delays caused by DNS problems
■ Changing the browsing timeout for virtual machine discovery
■ Changing timeout and logging values for vSphere
Please note the section where it tells you that log folders need to be created first.
Path for legacy log folders on a Linux/Appliance server is :