It's not that difficult to make a good guess though; In the file it shows the original database paths. If you're lucky, you didn't completely change the instance's folders and your instance folder is named somewhat like these.
- SQL Server 2005 uses MSSQL.<n> (counting up, starting at 1, n+1)
- SQL Server 2008 uses MSSQL10.<INSTANCENAME>
- SQL Server 2008R2 uses MSSQL10_50.<INSTANCENAME>