What does the following error mean:

NSS-2.70-5004: Volume OBFS1/SYS_SV is being deactived.
An I/O error (20204(zio.c[2179])) at block 1935298(file block
-1935298)(ZID 2295) has comprised volume integrity.

What is this? It always appears after the backup is run. We do not have a volume called SYS_SV. There are also similar messages for volumes OBFS1/SYS_SP and OBFS1/SYS_IV

The one for OBFS1/SYS_IV says the following:

NSS Volume OBFS1/SYS_IV is out of disk space.
There are no deleted files using disk space.
You may be low on disk space. Eiterh add more disks or delete some files.

Again we do not have a volume with that name and the volumes we do have, SYS and VOL1 have plenty of disk space.

We do have the open file agent for Backup Exec running with the backup.

Any ideas, thoughts or suggestions?