I am sorry but you are wrong. I used the script in the install instructions to change the permissions via SSH. The forum folder that's missing is modules/boonex/forum/data/attachments needs to be changed to 777
It was two identical wiki pages, and the link in Dolphin Install script was referring to the old one. I've corrected links and setup redirect from old link to the new one:
http://www.boonex.com/trac/dolphin/ticket/2596
But all forums permissions are there for a long time.
http://www.boonex.com/trac/dolphin/ticket/2596