jfergie I had that exact problem last night. Somehow, I had accidentally assigned my throttle to a button in the course of doing something else. Here's what I did.
(1) in the Map Controller Window, right hand column, look for Throttle 1. Is it assigned to a button, or to your actual throttle? You can change it to your throttle by highlighting your throttle, clicking on modify, then choose "Throttle 1" (I think it is under Analog Inputs) if I remember correctly.
(2) If you see no assignment of "Throttle 1" in the right hand window, then highlight your throttle control, click on Modify, and then choose Throttle 1. It should work just peachy.