I could not reproduce your error using SQL Backup 7.4.0.23. It doesn't make sense why there is a secondary data file named ftrow_KBIndex.ndf in the target full-text folder.
Could you please try restoring this backup on another server, and see if you get the same results?
Thanks.
Could you please try restoring this backup on another server, and see if you get the same results?
Thanks.