can you clarify "device shows up on the server", what server is it and how does it show up
your phone is trying to retrieve a config file from either CME or CUCM, this config file contains, among other things, the line/extension number for the phone.
If the device is configured on the server, and you have setup the network so that the device can reach this server then you are on the right track, we just need to find out why its not able to do this.
Can you also mention if you are expecting this phone to use sccp, sip or either.