problem: restoring backups

[saibo]

error i get when clicking on a backup-dump:

0: /usr/local/psa/admin/plib/common_func.php3:155
psaerror(string 'Unable "RestoreClient"::getDumpDescription(): Empty error message from utility.')
1: /usr/local/psa/admin/plib/backup/BackupInfo.php:119
BackupInfo->getDumpDesc()
2: /usr/local/psa/admin/plib/backup/BackupClientInfo.php:91
BackupClientInfo->parseBackupDesc()
3: /usr/local/psa/admin/plib/backup/BackupClientInfo.php:80
BackupClientInfo->domainListIni()
4: /usr/local/psa/admin/plib/backup/BackupClientInfo.php:21
BackupClientInfo->stepBegin()
5: /usr/local/psa/admin/plib/PMM/MigrationCObject.php:102
MigrationCObject->make()
6: /usr/local/psa/admin/htdocs/backup/backup_info.php:28


System:
plesk 8.1.0
fedora core 5


please advise
thx in advance
saibo