Both links on your website only work if you strip the numbers from your link. When I checked the epub with
ePubCheck, I got lots of error messages.
And since invalid input files usually translate into invalid output files, your generated .mobi file was most likely invalid, too.
The fact that it displays fine on a Kindle doesn't mean anything since the rendering engine will ignore certain errors.
However, the Amazon tools tend to be less tolerant.
To solve this problem, you'll need to change your script so that it generates valid ePub files.