I think i found a bug, when someone joins a group (Approval to join group) and the manager click on his group this window pops up (New user have joined your group - please activate them.).

It disappears when i click on it but when i click on manage pending users the windows pop up again. but when i click on it now i get a blank page.

If i click on the link on the top of the page (New users have joined your group - please activate them.) i dont get a blank page

hope you understand, sorry for my english hehe

I got the same issue. It's one of two serious bugs I found in Groupjive, and with these errors at this moment GroupJive cannot be used on working live community sities. But - after all - its still potentially very good extension. I believe GroupJive team will fix these errors soon.