hi i am using wlm 9 beta, and i have set a custom signature sound. The problem is that other people (who use wlm 9) don't hear my song, but one of the sounds that wlm had (like the guitar, the bass, the gong, etc). Why is this happening? plz help.

It's possible that they have over-ridden your sound with one of those themselves, but otherwise we can't really offer support for an early beta/alpha build demonstrating a potential new feature of a future Messenger version.