Why do my sound settings not save upon exit in Minecraft?

When I launch Minecraft, I have to go into the sounds menu and change the music volume level to 0. When I close Minecraft and reopen it, the sound level will be back at 100.

I am running 1.2.3 (I think). I am running several mods, but all of them seem to be functioning properly. I usually play Minecraft with music from my personal music library playing, but I am still able to hear creepers, and other in game sounds.

Is there a way to permanently set the in-game music in Minecraft to 0, or is this some kind of bug?

Copy and paste the following Path into the Start menu Search bar (Windows 7) or into Windows Explorer, if you are using XP (Win Key + R => type in the word "explorer" (no quotes) => Enter):

%appdata%\.minecraft

Now open options.txt and edit it to your liking. The area for music should read:

music:0.0

If the above Path variable does not work look for this (Windows 7):

C:\Users\YourUserName\AppData\Roaming\.minecraft

When you're finished, save the file and set it to read-only, so Minecraft wont change it again. Right-click options.txt => Properties => Click the Read-only raido button under attributes