Backups - Can't get exclusive lock

SUGGESTED

We have a BWG version 2013 SP7 with one Windows 7 SP1 x64 client and one Windows 8.1 x64 client running from a Windows 2003 server with Pervasive V10 SP3.


Recently when trying to backup we're getting an error saying that BWG can't get an exclusive lock to perform the backup. When trying to collect the exact error message, it finally backed up after three attempts.

Furthermore, our bookkeeper (the primary user, FYI I don't use the software at all - I'm only tech support) reports that backups have started taking increasing amounts of time to perform.

The server is a VM on an ESXi 5.5 system.  No other servers on that platform are having any issues, and they all share the same underlying disk, so I don't believe there is a disk issue.

Thanks in advance for any suggestions.