The 4shared link has been removed due to a 4shared support claim. The Adfoc.us website seems to be down for the other download link, so you can't get to the download.
If I can suggest one smart thing to do, it would be to upload a ZIP file of Pixelmon as an attachment to a post for easier downloading, then use Adf.ly in combination with a respectable file hosting service (Mediafire, because 4shared is horrible) for ad revenue.
Anywho, if anyone has 2.5.7, please re-upload it so I can download it.
EDIT: The Github is also presenting a 404 page....so there's that too.