I love the script, thanks for uploading it! :) There's one little thing you could improve though:
You can add a fourth parameter to guislider, so that it gets executed everytime you change something.
I mean these two lines in your script:

guislider mcsloud 0 255;
guislider mcssilent 0 255;

It would probably look something like this, I'm not sure tho, because I only took a short look at the script.

guislider mcsloud 0 255 [if (= $mctoggle 1) [musicvol $mcsloud]]
guislider mcssilent 0 255 [if (= $mctoggle 0) [musicvol $mcssilent]]

I'll rate it 5/5 if you change this little thing :)

finally i can insert my own musics, thanks.
edit:
when i go on a new map, the standart music is playing again. can you make the script keep the custom music playing? and can you make the custom music play from beginning?

Thanks for the script.

when are you going to update it?

-no more new music when loading a new map
-redons fix included (thx for that)

greez viruz

Note: you have to replace a default file. in general this is critical. nothing should happen atm, but for example a new release could mess things up.

the script is perfect for me now! thanks again, i waited a long time for a script like this.

bad thing is that it requires CLEAN ogg files, and not simple mp3 files that had changed extensions to .ogg, although media players read it alright! now this is a bad thing about games... :P

a couple hints... first off is you need to use an array to call the music... the play music function is not powerful enough ... this will involve most easiest to call in a exec of another file... that only contains a list of all the different playlist... next you need to call you music.cfg some where... simple type exec data/music.cfg... this will run your code... this needs put into any file that gets loaded on start up... also im not understanding y there needs to be 2 sliders for the music... you should make different presets but not 2 sliders... next the name of the menu should not be playlist... because it holds more than just the play list... this may seem picky but this can be a big issue for some... make a music menu that holds the basic functions... play stop previous next mute vol ... ect. then make a playlist button that opens the current playlist ... to fix the above problem make a separate array storing the file extension ...

chasester