Since I figured out a solution, I figured I'd post it here to share if it already hasn't come up. For some reason, whenever I try to play a music clip with Quicktime, Mozilla blacks out the player bar. I looked on the internet for a solution and saw someone mention running in compatibility mode for XP. I tried this and it worked. The Quicktime player bar is no longer blacked out in Mozilla. Unless there are any other know solutions, then I'll just stick to running Mozilla in compatibility mode. Here's the link where I found the solution. When streaming with quicktime the play, stop bar is all blacked out
I'm the second anonymous poster confirming the solution.