Mandatory information about my setup:

Have I searched the tickets before posting? Yes
Have I searched the forum before posting? Yes
Have I read the documentation before posting (which pages?)? YEs
Joomla! version: 2.5.16
PHP version: (unknown)
MySQL version: (unknown)
Matukio version: 2.2.4
Direct link to the page that shows the issue: see attachments


Description of my issue: I've got several 500 warnings on my production site, since I updated a subdomain with version 3.0.1. This happens f.i. with events, bookings and locations. (workaround is available: choose another item f.i. organizers). So, I thought something was mixed up with the trial of the new version and I wanted to install version 2.2.4. again, but then I got the message that it wasn't possible because you can't downgrade from 3.0.1 to 2.2.4.
So I assume some information is stored in a database table that both domains are sharing. Is that correct?

Kind regards,

Tim Hoogland