Firewire and target discs


I've a G5 running 10.4.2 and a G3 clamshell ibook running 9.1

Not too long ago I could use the G3 as a target disc with a firewire connection.

I don't know why, but this has stopped working. The icon for the G3 appears on the desktop but any attempt to access it results in the computer hanging up with the rainbow frisbee spinning forever.

I wiped the hard drive and reinstalled the operating system on the lap top. It wasn't working properly anyway taking several minutes to boot up for example.

Firewire connection still wouldn't work; so I connected the two machines with an ethernet cable. Now I can get the lap top to access the G5 but the G5 won't access the G3 - there is a message that the communication protocol is out of date or isn't supported.

I can exchange files which is what I needed to do.But is there any explanation or suggestions to get beyond this partial solution.