Um, no. You almost never want 'unbindall'.
Silly question perhaps, but since your binds look fine.. does the 'a' key work as expected normally? I've seen keyboards that are worn out in just such a way that holding your hand like you'd play a FPS means some keys work differently than when you're typing, so if you're testing the key's function by typing it may not be an accurate test. Maybe try with another keyboard, or in other games? Would at least rule out the "obvious" first.