Dear Team I'm trying to get the new version of Pro Site

Dear Team

I'm trying to get the new version of Pro Site to work. After some hours of testing I found the following warning after a customer selects a level and chooses the manual gataway to pay:

Warning: Illegal offset type in /home/webgango/public_html/wp-includes/plugin.php on line 85
Finalizing your site...

Thank you for submitting your request for manual payment. We will review your information and email you once your site has been activated or extended.

The email address we have for you is:

Any idea what causes this warning?
Thanks
Dominic