problem mounting target disk (dead ibook)

[Riannadana]

Hi, I have a dead ibook G4 that has some files on it I would like to transfer to my new computer. I think the logic board is toast but the harddrive seems to be working. I was successfully but very slowly transferring files using firewire target disk mode, disk utilities application and after a failed repair the harddrive would be mounted with recommendation that I backup my files since the drive can't be repaired. I had to shut down the computer over the weekend and stop the file transfer because I was using a work computer for the transfer. For some reason I can no longer get the drive to mount anymore though it still shows up as a drive in disk utilities. It does not show up as a drive when I type 'df' in Terminal window however. I guess that is because it is not a mounted device? Any advice would be hugely appreciated.