Can you get into Gopher at all? If so, go to File | Backup and try performing a Backup followed by a Restore (this forces Gopher to perform maintenance on the database file). If that doesn't work, try emailing your file to email@example.com and we'll try to repair it for you.
Are you running XP or Vista? If so, you can use the system restore function to go back to an earlier date, with an earlier database before it became corrupt. To use System Restore, go to Start | All Programs | Accessories | System Tools | System Restore. You can pick the most recent date prior to the problem.
I tried to do a backup and restore. When I tried the restore from the c drive, I got a message that the zip drive wasn't decompressing. So I did a backup to an external flashdrive. When I tried to restore from that, I got a message that connection was lost to database at the step gbak: restoring domain BOOLEAN.