do_backup is already running?

[bamaster]

I seem to be getting the following error a few days a week.

"Encountered error when do_backup is already running. Backup cannot start twice!"

I'm running Plesk 7.5.4 on RedHat EL3

Here are the logs for my 4PSA Total Backup script:

Sep 21, 2006 04:35:05 alert mail sent to email_address - Success
Sep 21, 2006 04:35:05 do_backup is already running. Backup cannot start twice! - Failure
Sep 21, 2006 04:35:04 Using active FTP transfer mode - Success
Sep 21, 2006 04:35:04 backup session 1 started - Success
Sep 20, 2006 04:35:02 tar backup with gzip compression started - Success
Sep 20, 2006 04:35:01 Using active FTP transfer mode - Success
Sep 20, 2006 04:35:00 backup session 1 started - Success


Notice that yesterday it was fine, but today it found an error. It seems once the backup is complete, it doesn't shut down the service.

Any advice how to resolve this?