Hi,
Warning: array_merge(): Argument #2 is not an array in D:\server\website\htdocs\classified\wp-content\themes\classipress\framework\scb\Options.php on line 44
The "themes\classipress" in there tells you that the message is coming from the Classipress theme.... they'd be the people who could say how to interpret it in the context of their code...
(It may just be that you should turn off the display of debugging messages on your website - it's not normal in production to have PHP send its messages to the browser, instead of to a log file).
Best wishes,
David