having a problem in conecting with airport extreme 802.11n wi-fi on ipad2, having a problem in conecting with airport extreme 802.11n wi-fi on ipad2

when i was trying to conect with the airport extreme 802.11n wi-fi on my ipad 2, having problem in my ipad saying that your airport base station does not have a valid IP address. make sure your airport base station is connected to your broadband modem or local network....n also another message is this airport base station doisn't have any DNS server addresses and might have trouble connecting to the internet... bt in laptop can use this internet without any having problem.... so freinds any idia to solve this problem.??