Is the problem with Safari that I can't seem to download mp3s?

I recently got a nice little app that lets me post audio to twitter.

It's called mp3twit

I uploaded some tracks I own all the rights to, but even tho it's confirmed that they uploaded, I cannot play them online nor can I download them. They are not AAC files. They are .mp3 files.

If I try to download I do "download linked file as..." and it goes into my download folder but the file shows up as an html file or else, when it DOES know it's an mp3 it shows up with zero bytes.

I've worked with other people's files listed on that site. Some download properly and are about 2 mb. I can hear them online as well. But most don't and have the same problem as mine. But they are listed as "Popular tracks" and the site shows multiple plays and downloads for them, so SOMEBODY is able to download them. Is there any trick that will let me use this easy app? does anybody have any suggestions as to why it doesn't work? I don't really think it's Safari because I tried using Firefox as well. I'm using the latest version of Safari and Java and OS 10.8.3 on an imac.