Error message on recurring events page

Hi,

I am trying to list some recurring events but keep getting the following error message at the top of each event page.

Warning: date() expects parameter 2 to be integer, string given in /homepages/12/d675978875/htdocs/clickandbuilds/Clungunford/wp-includes/functions.php on line 114

I get the same for lines 116, 118 and 119. This only occurs with the recurring events.

Any thoughts how I can get rid of it. I am no coding expert! The format for dates in the plug-in settings is l, F j, Y

Thanks,
Max