This URL is generated from the "Browse Host" feature by BearShare. This way, you can still use a regular browser to download the file. Without it, all browser are blocked (that is, browser like MSIE, Opera, etc.). This was done in response to public "Gnutella Portals" which allowed everyone to leech, but not return anything for it (thus causing a big imbalance, especially if the Gnutella client serving the browser has limited upload slots).

Regular Gnutella -> Gnutella download requests work fine for BearShare. Download Bearshare on your own PC, connect to it with another vendor's client and try to download something. You'll see it'll work.