Its either not fully into the lockdown position or the limit switches at the front are not operating. Have you tried adjusting the operating levers on the switches themselves the two switches are at the front of the AFT and can be easily see when the AFT is raised.
![Image](http://www.g8dhe.net/bongo_images/aft/23805_betterdiagram_122_255lo.jpg)
![](https://images1-focus-opensocial.googleusercontent.com/gadgets/proxy?url=http://www.g8dhe.net/bongo_images/aft/AFT_Limit_switch_front.jpg&container=focus&resize_w=750)