Can't start filesharing



I can't start filesharing in OS X running on iBokk/300/96MB/3GB. I've tried with or without AppleTalk made active, it just won't start. Why?

I have the same problem, also with an iBook. Nothing works w/ or wo/ AppleTalk. I can't get any connection to the outside world going, as a matter of fact. I'm wondering if the File Sharing problems are somehow related to the PPP connect maladies I'm experiencing. Any suggestions?
My brother and I both have a Powerbook G3 333.

On mine, I have no problem starting up file sharing. It starts and stays started.

On my brothers, clicking file sharing seems to work, then it stops. No matter how many times you do it, it seems to try then gives up.

Have not found a fix either.