The downloads of IPS files have changed.
To download files manually you need to go through the supported Cisco.com download website.
http://tools.cisco.com/support/downloads/go/Redirect.x?mdfid=278875311
It was unknown at the time of the change that users had been directly accessing the FTP server. When the download methods changed, the main download page was modified to point to the new location.
It was assumed that users were either accessing files through the main download page and would see the notifications that were posted on that page. OR that users were using CSM (or the sensor itself) for automatic downloads, and the automatic downloads used an internal API that was dynamically modified to point to the new locations.
Direct access to an FTP server for downloading the files is not supported, and users will need to go through the download web site.