now the mid router (which is in between my server and their server) is giving 172.20.0.x DHCP and subnet 255.255.255.0, and the windows DHCP server is 10.10.10.x subnet 255.255.255.0 and i am still getting the same thing, just like before.

about your questions, there's only one PC which is the windows server PC behind the mid-router between the windows server and the ISP router, then the cliens those would connect to the windows server (the end users) may reach up to 200 - 250 client.

and i am using the third DHCP server (windows server) to control bandwith and also to have multi roles , 3 roles for each group.

So all clients will be getting DHCP from the Windows Server?

Yes, but according to their role, means some will have full access (guests) and others won't (some of employees)

Then you don't need the other two DHCP servers. Assign them static IP addresses for their LAN ports. Set your Gateway on the Server 2003 DHCP setting to the IP of the mid router. On the mid router set the Gateway address to the IP of the ISP router and you should be good to go.

How come!!, i agree with you that i don't need the DHCP mid-way router which is between the ISP's router and the windows server at my end, but i do need the windows server to be DHCP.