It looks like your DHCP, DNS, and MAC settings are okay.

Are there any other wireless cards operating on the network? Sometimes 2 different wireless card brands will cause conflicts with each other. Are you running a card with a different brand than the router? Check to see if the router is set on Turbo G or Speed Boost settings (all are proprietary settings). Try a standard "G" setting.

Did you check your WEPS and WPA settings?