No, but in order to connect to or from a machine running Leopard, you'll need to follow these tutorials, and ensure you have AppleShare Client 3.8 (which requires System 7.6) installed.

Hmm, you don't happen to have a copy of OS 9 on the G4 you could boot into, do you? Networking System 7 and Leopard *is* doable, but if you can boot the G4 into OS 9, that'll make things a *lot* easier.