Hi Noc,
This upgrade *** (note the reference to 6.1(1x) will require you to order the Media Kits. You can only use the downloadable files for upgrades from CUCM 6.1(1) not 6.0(1);
Use the Product Upgrade Tool (PUT) or the PUT that is for registered customers only to obtain a media kit and license or to purchase the upgrade from Cisco Sales.
To use the PUT, you must enter your Cisco contract number (Smartnet, SASU or ESW) and request the CD/CD set. If you do not have a contract for Cisco Unified Communications Manager, you must purchase the upgrade from Cisco Sales.
PUT is located here;
http://tools.cisco.com/gct/Upgrade/jsp/index.jsp
Here is where this is referenced :)
***Caution: Use the ISO files that are mentioned in the "Upgrading from Cisco Unified Communications Manager Release 6.0.(1a) or higher to Release 6.1(2) by Using the UCSInstall File" section for upgrades from 6.1(1x)only.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/rel_notes/6_1_2/cucm-rel_note-612.html#wp396032
Hope this helps!
Rob