setInterval active forever?

I have a mc with a setInterval that calls a function repeatedly to load external jpgs

The mc in question is a little movie in a bigger movie, and plays only when you click button A.

Problem: When the mc is playing, you click button B to play a different mc in it’s place. However, the output window begins to throw up ‘path not found’ errors - so the setInterval is still active, even though the mc is no longer visible

Do I need to clear setInterval when I click button B?