Mac OSX hard disk gives invalid PEOF - how do I back up data?
Do you have another Mac? If so you can connect the failed Mac to your other mac via firewire and you target disk mode.

Power off the failed mac, connect it to the working mac via firewire. (The working mac can already be powered on) Boot the failed mac and immediately hold down the T key on the failed mac. Continue holding it until the firewire icon shows up on screen. You should then see the mac mounted on the working mac. 

Link with more details http://support.apple.com/kb/ht1661

Also an interesting link with some details on your error http://support.apple.com/kb/TA21624?viewlocale=en_US