SQL Error - [function.array-merge]

Hi David,

Hope all is going well.

I wondered if you might be able to tell me what could be causing the error below to appear:

Warning: array_merge() [function.array-merge]: Argument #2 is not an array in /home/content/43/HostingRef/html/Sites/MySite/pt/pt/products.php on line 171

Warning: array_merge() [function.array-merge]: Argument #2 is not an array in /home/content/43/HostingRef/html/Sites/MySite/pt/pt/products.php on line 171

I switched on debug mode but nothing additional was captured.

The error has only recently started appearing and not for all products which makes me wonder if it's data for a particular product that is causing it?

Thanks in advance.

Regards
Chris