I see several other folks have posted this problem in the html_header.php file:

PHP Warning: extract() [<a href='function.extract'>function.extract</a>]: First argument should be an array in html_header.php on line 50
PHP Warning: extract() [<a href='function.extract'>function.extract</a>]: First argument should be an array in html_header.php on line 51

Referred lines in the file are:

extract($product_info_metatags->fields);
extract($category_metatags->fields);

I also see where it was brushed-off as frivolous because it doesn't effect the user's experience. Well, it's not frivolous. I received a notice from my host provider threatening to shutdown my site due to an overload of files (100,000+). I checked the cache file and they were all the above error. Each time my site loads it generates from 5 to 10 error log files. I had to ask the hosting company to remove them because I couldn't. I tried using Filezilla and cPanel to delete the files and they immediately returned. This file overload also prevented my auto backup cron job from running because of the file overload.

We need a correction to this please.