Does it work on a new created document? If no – there maybe something wrong with the output styles listed.
Make a new copy of your document and work on that. (You can try copy and paste everything except the last paragraph symbol).
– Try changing the style by “selecting another style” and picking one from the full list?
Try turning off Instant formating and then on again.
Try turning off instant formating and then convert citations and bibliography to unformatted citations, then try update citation and bibliography.
Make a new copy of your document and work on that.
if a new document works then the current document maybe corrupted? Are the temporary citations (which is what those are) are grey when you click in one?
Try turning off instant formating and then convert citations and bibliography to unformatted citations, (you may get an error message saying there aren’t any formated citations) – Then remove field codes (select all and Ctrl+6) and then try update citation and bibliography.
These steps are outlined in more detail here: http://endnote.com/kb/81143