Ableton midi mapping issue

Hello everybody, I just got ableton and I am really excited to start learning how to use it. I've been watching some basic videos of how to use it but I have run into a problem. When I go to map a function to my midi controller (MDP26) it will not map the function I select. Instead it will map a different unselected function to the midi pad. I am wondering if I need to edit the midi notes in the akai editing software or if I need to do something to ableton. The MPD26 is also set to its LIVE preset. I set the MPD26 up correctly in ableton's preferences but ableton just wont let me map the selected parameter to the button I want. Any help would be GREATLY appreciated. Thank you guys.