Someone else had same issue two weeks ago, http://www.gnutellaforums.com/open-d...e-startup.html

First try this one BearShare Test 5.1.0b25.rar
If the so-called 32+64 bit version does not install for you, try the BearStart version, BearShare 5 stuff - filecloud.io
If you have issues downloading from filecloud, disable your adblocker for that site and refresh the page.

Please let us know how things go.