Yeah I've had zero luck with this also. What lionz recommends sets the angle of the bullet SPRITE, but does not change the angle of motion.
If you try to change the angle of motion, the script only allows for a single number (angle), and won't let you input Mouse.X and Mouse.Y.
It seems that spawning a bullet, the bullet will match the angle of the object that spawned it and travel in the direction (that's how it works in the Ghost Hunt tutorial). I've yet to figure out how to take a stationary object and spawn a bullet that flies towards the pointer.