what exactly do you mean by "database backup"? If it is a backup of a MS SQL Server database, it does not contain 1CV7.DD. Unlike 1C:Enterprise 8, 1C:Enterprise 7 stores metadata files and database schema files in the infobase directory. If this directory is gone, there is no way to recover 1CV7.DD using a database backup.
I doubt that 1CV7.DD can be available online. However, if your configuration was not customized, the file from another infobase that used the same configuration might help (provided that you find a user willing to share it).