Since there’s currently a filesystem error, simply restoring the disk image you made will also restore the filesystem error. Like I said above, all you need to do is copy the contents of your games partition to another partition, reformat, and copy back.
Set up a hardfile in WinUAE with enough capacity to hold the contents of your games partition. Then copy everything to that hardfile using either DOpus or the shell (copy gamespartition:#? backuppartition: all clone).
I’m assuming that the error on your games partition prevents writing to the partition but that you can still read from it. If you can’t read it, i.e., if you can’t copy the files off, you’ll need to look into a fix-in-place utility to correct the filesystem error, but that’s beyond my knowledge for PFS.