Just figured out how to fix the problem...
After you unzip the files you have to open idoser, click on options, and click associate.
Everything should work after that.
Cheers!

Okay, I downloaded the idoser player, which came with the 2 free doses which work fine, but when I got the other free doses (which came as zip files) they didn't work. Yes, I have unzipped them, but when I try to play them on idoser a window pops up and says "Error 52, bad source or file" ...