Fixed the problem.
Not sure why but I had version 1.3.3 of the Participants Database. I had installed it from the plugin search in the admin panel. When I looked at the code it didn’t have all of the code for search or sort.
I have now downloaded version 1.3.7 from http://ww.wp.xz.cn/extend/plugins/participants-database/ and installed manually at it works fine now.
Adam
