Sliding menu, disabling buttons?

Hi, I’ve created a sliding menu that has a left button and a right button. Each button slides a background movieclip to the left or right. The background mc eases into position when one of the buttons is clicked. Problem is that buttons can still be clicked while the mc is easing into position. This throws off my x coordinate positioning of the mc. I’ve tried disabling the buttons and enabling them again at a few different points in my code. I’ve also tried using a time delay to enable the buttons but my logic isn’t working. I’ve stripped the code that was not working out. If someone could take a look at my code and maybe point me in the right direction I would be appreciative. I’m wondering if I should be using different logic to move the background. I’m basically just moving the mc._x + or - 100 px when a button is clicked. Here’s the .fla