That's interesting. Looking at those, I can locate the source of the first and the third. For the first, (Terrax's music), it is "natively" with bad samples. I mean, it is as is in the demo it comes from:
http://janeway.exotica.org.uk/release.php?id=962
For the third, I guess everybody copied on each other a defective version. I've fixed the one on AMP now. It comes from the following demo (where it is with valid samples:
http://janeway.exotica.org.uk/release.php?id=7041
I have no idea about the source of the second music. some help ?