Thanks for the input! I've atually tried doing that but it didn't change anything.. in any case, since I've got the text object showing the variable VolumeMusic at all times, I could see it was working. It went all the way down to -60, waited for a second, then went all the way up to -10 without a problem.
I'm trying something now that I -think- it might've fixed my problem, but I'm not sure, I'll report back..
Welp, it didn't work.
If I set the function like this:
<img src="http://i.imgur.com/Sm0AuzG.png" border="0" />
It works perfectly. But as soon as I try to change the volume, wait, then change it again, the music never plays..