Ok then that is a conflict with the style then. It has been reported before, but I don't remember if it can be resolved. I will do come looking around in a bit.
I found the thread with that issue in it, and Fillip H.'s response who is the dev of the mod said this:
That's an issue that can happen on some custom skins for reasons I have not been able to determine. I've also been unable to fix it, in spite of trying for pretty much every update of vBShout.
Unfortunately it doesn't look like it'll be fixed any time soon
It's a shame, it seems like the product is only mainly built to be compatible with the default vBulletin skin, which not many use :/
I just wish things would work more smoother.
I'll see if I can have the designer possibly look into fixing this.
It made months I was wondering why the shoutbox caused the forumhome page was soooo long to load (a freeze of Firefox of about 4-5 secondes at refresh)... I've tested to turn off the sound and now it's working as it should be. THANKS !!!