Flash Newbie - HELP!

this may seem like a real elementary problem, but again I am new to flash, so please bare with me. I am trying to create a nav bar, but am having issues with the button. when i put the movie clip in the down state (which I thought was correct) you have to hold down on the mouse for the flash to work, rather than just a simple click. am I missing something?

To all those seasoned vets out there - please help