Problem configuring Cisco 4960 IP Phone?

Well, I have been trying to setup this Cisco 4960 IP phone(version 7.2). I am trying to put this phone on a system that already has a few other phones(NOT CISCO, all other phones working properly). For some reason I cannot figure out how to get the phone to work right. If I power it on and let it sit it will eventually go to Authentication Rejected. I have a feeling this is because the TFTP is installed on 192.168.x.5(the server) and on the network settings screen on the Cisco Phone it is displaying 192.168.x.1(the wireless router). Now, someone else setup this system so I am trying to work with what I have without having to do a total reinstall. I am working with Linux Box, has FreePBX(believe it is 2.8.0) and Asterisk installed. I believe it is Asterisk double check later). Now one thing I think might be the issue, but having problems with is the SIP.cnf file. When I goto the TFTPBOOT folder I do not see any files in this directory. I tried downloading a default config and modifing it to my TFTP, Gateway and user/pass settings. I also put the macaddress after SIPmachere.cnf. Really would like to figure this out. Any help would be greatly appreciated.