*uses his GREAT skills of translating that sentence*
Hmm, you mean to make another admin not to be able to ban or delete the original admin? Well, I don't know if he can do that but to be sure just disable him the option to change User Permissions. You can edit that at Usergroup Permissions... then select Administrators Permissions and select the admin you want to edit.
You also want the admin to be unable to delete forums? Just set "Can Administer Forums" to "No".
Hope this helps you.