Seaquel
SQL Server error code

SQL Server error 3078

SQL Server raises error 3078 at severity 16, which marks a problem with the query or data that you can correct.

The file name "%ls" is invalid as a backup device name for the specified device type. Reissue the BACKUP statement with a valid file name and device type.
Msg3078
Severity16
Group3000–3999

Source: Database Engine events and errors