Start the game, create your profile and play for a while. Save and exit. 
Right click on the avatar.exe in the game folder or on your desktop. Go 
to Properties. On the Target line, add "-GameProfile_GodMode 1" at the end.
It should read like this:
E:\Program Files\Ubisoft\James Cameron's AVATAR - THE GAME\bin\Avatar.exe"
 "-GameProfile_GodMode 1"

Accept the settings. Click OK. Start the game and you'll be able to play 
your profile in God Mode.