TSM 5.1.9.0 on win2K server.

I'm failing to delete the volume histories on the following volumes
(LTO-2 tapes):

tsm: TSM>q libv

Library Name   Volume Name   Status       Owner        Last Use    Home
------------   -----------   ----------   ----------   ---------   ----
LB6.0.0.3      ITG010L2      Private                   DbBackup    41
LB6.0.0.3      ITG033L2      Private                   DbBackup    64
LB6.0.0.3      ITG044L2      Private                   DbBackup    48

The command I run is:

tsm: TSM>del volhist type=dbbackup todate=today

Do you wish to proceed? (Yes (Y)/No (N)) yes
ANR2467I DELETE VOLHISTORY: 0 sequential volume history entries were
successfully deleted.

None of the dbbackup volumes are deleted though. Why? This has always
worked in the past. Anyone have any idea? Logs don't give any error:

ANR2017I Administrator DUDE issued command: DELETE VOLHISTORY
type=dbbackup todate=today
ANR2467I DELETE VOLHISTORY: 0 sequential volume history entries were
successfully deleted.

I need an answer fast as I've only got 1 scratch tape left because the
dbbackups keep stealing tapes. The database is only 14MB so it should fit
on one tape easy. Thanks in advance,

Alex