ISOs and images for PC-BSD's rolling release have been erased.

All packages and binaries for PC-BSD have been switched from mirrors sites to Contents Delivery Network (e.g. BitTorrent).
PC-BSD Now Uses a CDN

But, ISOs and images for PC-BSD's rolling release have also been erased, so that the site http://mirrors.isc.org/pub/pcbsd/9.1-RELEASE/ is now "404 - Not Found".

The information above is now obsoleted. Please check current information:
phosphorescence: ISOs and images for PC-BSD's rolling release have been re-deployed