[Plugin: amr users] Search is not working

I am using AMR Users 3.3.6. with WP 3.3.2 and the twenty-ten theme. I have a fairly basic list of members which I want to display on my site and I have accomplished this using the relevant shortcode. The list displays fine. However, the ‘search users’ button does not appear to be functioning. Whatever string of characters I input, there is no result. The Search button justs ‘clicks’ and the whole screen just stays the same. Was wondering if anyone else had this problem and if so, if there is a solution?
TIA