First off I noticed there is a feed// in front of the rss urls – did you try to change somethings in the plugin?
(feed://http//tmblr.net/groups/wantoks-bilong-png/forum/topic/welkam/feed/)
I’ve only tested this against the bp-default theme – possible a new theme may cause an issue but I need some php debug/error reporting logs in order to find the root issue (just by looking at the site – i don’t know what is causing the problem) Seems the bp-forum-extras-group-topic-feed.php and bp-forum-extras-group-forum-feed.php are loading up but something is causing it to fail even before the first rss element is outputted to the screen.
Not sure about the sticky, as that should not play any role with the rss feeds. (i just tested on 2 instances and it works fine but then again you may have another error causing both sticky and rss feeds to fail)
As for the signature – you’ll need to change up the css for that class to suit your needs.
(default style inserted by the plugin is .signature { width: 75%; padding:5px 0px 0px 5px; border-top:1px solid #ccc; font-size:90%; color:#444; }
