I saw this problem recently. The backup would only work when set to find the system using "VM Display name". For some reason the other options would not be able to find an offline VM.
What is the underlying error code from the detailed status?
You will have to look at your application logs for more information. Netbackup runs the script and waits for the backup image to be passed along from SQL. You have to troubleshoot what is happening on the SQL server.
There are many things that coul...