File Sharing in Jaguar - Problem with Firewall

[rabatjoie]

I am trying to hook my and my girlfriend's powerbook together via ethernet cable. Turned filesharing on on both computers, but i can only access her computer from mine - not the other way round. in her sharing panel in system preferences, it says at the bottom, that her computer can be accessed via afp under address blabla... on my computer, it doesn't, although i got filesharing turned on. i figured it could have something to do with this: if i click on the firewall tab in the sharing panel, i get the notification that there is other firewall software running on my computer and therefore the built-in firewall is not available... the problem is, i do not have any other firewall software installed... at least none that i know of! ... anybody's got a clue how to find a solution to this?