One thing that you can do is upgrade to MP3 and then contact support. they will supply you with two post MP3 patches that will fix the problem. I know this works because I had the same problem and it fixed it 100% if you can believe that..
the two files that support will give you are
nbjm.exe
nbpem.exe
Symantec NetBackup Enterprise Server
Release 6.0
Patch MP3
DATE: 07/30
this will take care of your problems with scheduler