In your SQL Server COM folder, there is a file named sqlvdi.dll. This is the backup library that SQL Backup uses. Try registering this dll manually e.g.
regsvr32 "C:\\Program Files\\Microsoft SQL Server\\80\\COM\\sqlvdi.dll"
This COM library might sometimes get unregistered when you install one instance of SQL Server, then install another instance, and later uninstall the later instance.
SQL Backup Consultant Developer
Associate, Yohz SoftwareBeyond compression
- SQL Backup goodies under the hood, updated for version 8