Buttons - what am I missing?

I have created several buttons in a .fla I created.
When the user puts the cursor over a button either a graphic or some text that I put in the “over” state keyframe will appear(depending on which button the cursor is over).
When I use control --> enable simple buttons, all the buttons appear to work properly.
When I test the movie, all the buttons that are suppose to show a graphic work fine, but those that are suppose to display text seem to be unstable, the text flickers and will not stay up on the screen.