Hi Malek,
Support for the 7941 and 7961 was not added until CCM 4.1(3)SR1. So you will need to migrate to at least this SR;
Supported CallManager Versions
The Cisco IP Phone 7961G and 7941G firmware is supported on these Cisco CallManager versions:
Cisco CallManager version 4.1(3) SR1 or later
Cisco CallManager version 4.0(2) SR2b or later
Cisco CallManager version 3.3(5) SR1 or later
You should install the following device packs for these Cisco CallManager versions.
4.1(3) SR1 ciscocm.4-1-DevPack-23.exe, or later
http://www.cisco.com/en/US/products/hw/phones/ps379/prod_release_note09186a00804fcab9.html
Hope this helps!
Rob