What would cause a cub cadet LT 1045 series 1000 to neither go forward or backward when the pedal is presses forward or backward?

The transmission isn't engaged. I just rolled my tractor off the ramp...after disengaging the transmission...then I got on, started it, and it wouldn't move. After 10 minutes of triplechecking the parking break, and randomly pushing buttons and shifting gears...I realized the transmission was still disengaged.

It's the little lever on the back of the mower. There's a sticker that tells you what to do.