Visitor Tracking Stopped Logging Visitors

Hi,



I need a little expert help. I am using CS Cart version 2.2.4 and about a week ago my visitor tracking stopped logging visitors to the site but strangely still tracks robots ( please see screen shot).



The site has definitely had visitors as we have made sales over this period.



Any ideas?

Screen shot 2013-05-11 at 09.16.09.png