IOS 7 Firmware not compatible?

I paid for UDID activation and downloaded the correct firmware however I repeatedly get "firmware not compatible" message. I'm running iTunes version 11.0.4. I have an 8gb Iphone 4, with AT&T, running iOS 6.1.3 I downloaded the GSM version titled: iPhone3, 1_7.0_11A4372q_Restore. I have tried multiple times to delete and re-download the beta. I have tried both shift-click "Update" and "Restore" options on iTunes. I still get the message "firmware not compatible." I have also tried with the phone in DFU mode and in normal mode, but still no luck. What am I doing wrong?

I'm new to developing and am also in college for video game design. I have a tight budget so I could not pay for my own developer account. I have a passion for developing and I wish to learn by trial and error as well. Please no smartass comments about how only hard core developers should have the beta, everyone was a noob at one point.

You have an iPhone 4.
You are trying to install iPhone3.
You need the correct version.

I can't believe you paid for UDID activation. Noone needs it.
Download the correct version from the links given in the below post, follow the entire post, and you will have an already activated ios 7 beta version… No payment, no activation…
Darn those who duped you…
Never pay again for beta versions…

http://itsanant.blogspot.in/2013/07/upgrade-ipad-or-iphone-to-ios-7-beta-2.html