Ok you two real problems looks like you have installed your forum into your route of your site.
http://www.islandgreeneast.info/styl.../site_logo.gif should be
http://www.islandgreeneast.info/foru.../site_logo.gif
so if you had any files on you server off the same name ie: index.php or any folders that had the same name have now been over written.
Forums or any other install should always be installed into a folder, unless it is the front end off your site.
if you installed your forum though fantastico then you would not have a copy on your desktop. but you can get to it though ftp manager.
would advise going to phpbb.com and downloading from there.
also the forum link on your site goes to the admin page.