Install and configure ubuntu 5.10 server

I am a linux enthusiast but still abit raw. I have a debian server with 2 NICs, on for the external network and the other LAN.My problem is that I cannot get this machine to distribute IPs for my win98 clients by DHCP. My ISP on the other hand gives dynamic IPs. The signal from the IP gets to this debian box.
can someone tell me what I can do.I have checked my dhcpd.conf and I think it’s ok.

I also now feel like switching to ubuntu 5.10 server to solve this problem. Does someone know if there’s a good step by step tutorial for this

Derick