CExBackup::backupService:HrESEBackupSetup: Error Number 0xc7fe1f45: Instance not found.
The drive where the transaction log files are saved is full.
To resolve this issue, remove un-needed log files to another disk drive to free disk space.
Refer to the following Microsoft Knowledge Base article for instructions:
For more information, follow article number to view the article in the Microsoft Knowledge Base:
How to remove Exchange Server transaction log files: