unable to decode audio data
wut website do you use 2 download the music?
I downloaded the file called "YOUVE BEEN GNOMED WITH THE POLICE" from this Scratch project:
https://scratch.mit.edu/projects/313773362/
What Scratch exports doesn't seem to be readable by Chrome. But I was able to use VLC to convert it to mp3, which then can be read by Snap.
I can't believe I just made a "nightcore" project 
Scratch sounds (especially ones from older projects) are sometimes stored in a non-standard ADPCM format which web browsers can't natively decode. You can either do what Jens did or use Snapinator, which fixes the sounds automatically.