You cannot perform the restore operation because the SharePoint Portal Administration (SPSAdmin) service has acquired an exclusive lock on the configuration database.
To resolve this issue execute the following steps:
Ensure that there is only one restore operation currently running. If you are sure that there are no operations that currently require a lock on the configuration database, stop and start the Microsoft SharePoint Portal Server Search (SharePointPSSearch) service, and then retry the backup operation. The service can be stopped and restarted using Computer Management Console:
Start Computer Management Console