Gerald,
3.1 is a pretty old version. But it includes a script
bin/BackupPC_fixupBackupSummary which tries to re-create the backups file.
I'd recommend making a backup copy of the backups file:
su backuppc
cd /var/lib/backuppc/pc/wpg-sbs.erlphase.com
cp backups backups.save
BackupPC 3.1
Ubuntu 14.04
The web page doesn't show some of my early backups for one of my PCs.
When I check the storage, I still see all my saved backup directories.
Backup# Type Filled Level Start Date Duration/mins
Age/days Server Backup Path
904 full yes 0