Initializing Airport Extreme Question

Yesterday I purchased an Airport Extreme to replace the Airport Express I was using in my home wireless network. My network was working fine with the Express, but I wanted more capability. I unplugged the Express and plugged in the Extreme. It powered up, but ended the power up cycle with a flashing amber light. I decided to go ahead and try to initialize the Extreme with my 17" MacBook Pro ( OSX Version 10.9.1 ) using its Airport Utility Version 6.3.2. My computer recognized the AirPort Extreme and I went through the steps of naming the network, base station name, password, etc.

After the setup was complete, the Airport Utility showed an image of the internet and the Extreme with a yellow dot by internet. The status box on the right hand side of the extreme showed yellow for No DNS Servers, PPPoE Server, and Internet Connection. It was not working.

I purchased the Airport Extreme from MACMALL. It was listed as "Apple Airport Extreme (2013)". The Extreme box listed the Extreme as "AirPort Extreme 802.11 ac" with model No. A1521. My Airport Utility said it's software version was 7.7.2.

My internet service is Earthlink and the modem they supplied me is an ZyXEL P-600 series modem.

My internet service is via telephone wire to the modem which is plugged into the Extreme via a short ethernet cable. It is the same setup as with the Express. I know there are not problems with the modem or the cabling since it works with the Express.

I am frustrated since it seems as though the Extreme just will not power up and connect to the modem internet without any initialization, but the Express will. Please help me.