DHCP and RAW socket and C

Hi
This is my first post and am a newbie to network programming.
My currrent assignment is concerned with DHCP client server
programming and need some help with that.

I need to request two IP addresses on the client side from the server.
I have a single LAN card and the request is sent from client on the
same LAN card. The first request contains the preffered IP address and
the MAc address and is sent using sendto() function inside another
function send_packet(). The second request contains a preffered IP
address and a third parth MAC address(not the same address on which
the client is working). In sendto() function i get a message "such a
device does not exist". Not surprised by that, but i need to get this
working. Ne ideas from ne one.
I heard i can use RAW sockets instead of Datagram. Will this put the
card in promiscous mode? Is this a solution?

http://www.isc.org/index.pl?/sw/dhcp/

This is the code im using at the client and server side to run the
daemons.

Pls help

Thanks in advance