Trying to boot into iMac to retrieve personal files

I cannot boot into my iMac. It hangs when I boot.

I was trying to upgrade from 10.4 to 10.6, which failed during the upgrade. At that point I could no longer access my Macintosh HD. I can boot into "target" mode, but my MacBook is not recognizing the iMac HD when I plug in my firewire cable.

My goal is to pull all of my personal files, wipe the HD, and then install 10.6.

Any recommendations?

Thanks

 

Just tried that. After 40 seconds I get a message "you need to restart blah, blah, blah..." that is the message I get in any mode except 'target"