Events+ and MarketPress Not Working Together

I am getting the following error after I try to register for an event.

Warning: Cannot modify header information - headers already sent by (output started at /home/content/35/11098935/html/wp-content/themes/genesis/lib/structure/header.php:63) in /marketpress/includes/common/class-mp-cart.php on line 2104

I have tried to turn off all my plugins and the problem is still persisting. I have also tried to change to the twenty 15 theme and am getting the same error.

I have also looked at line 2014 of marketpress and it seems to have something to do with the cookies files...

I deleted all my cookies and cleared my cache and the problem is still there.

Support access is ACTIVE until November 6, 2015 9:19 am

The error is being displayed on this page:

You will need to register as a free/student member is you want to try to sign up for the event and test the error. You can do that here: