Not sure if your last reply meant that you found the problem or not, but the phone should be supported by your switch. Cisco's PoE Requirements FAQ mentions that the 7910 uses Cisco Prestandard PoE, but the Data Sheet for the 3560v2 shows support for Prestandard PoE, so the phone should work. Check the running-configuration for the port you are plugging into and make sure that something like "power inline never" is not present. If this is present, it will stop the switch from providing power on that port. Also, check "show power inline" to make sure the switch recognizes that it is capable of delivering power to the phone- if you have other PoE devices connected, the switch could be out of power for PoE devices.
