How do I play quake 3 arena with a PC over LAN?

[Paul Allsopp]

I'm trying to play quake 3 arena with my flatmate who has a windoze 98 
PC.  I've created a quake server game on my cube, and the PC can see 
the cube in the list of local quake servers but cannot connect.  I've 
turned off my firewall.  can't think what else to do.  anyone have any 
ideas? I'm running Q3A 1.32 on OSX 10.2.3.

Thanks for any help...