Warning: array_key_exists() error after upgrade

i found the reference, but how to solve

function in_category( $category ) { // Check if the current post is in the given category
global $post, $blog_id;

$categories = get_object_term_cache($post->ID, ‘category’);
if ( false === $categories )
$categories = wp_get_object_terms($post->ID, ‘category’);
if(array_key_exists($category, $categories))
return true;
else
return false;
}

if(array_key_exists($category, $categories))

it’s that line, I have the same error! Someone please help, I don’t know what it means to put a string or integer?

Warning: array_key_exists() [function.array-key-exists]: The first argument should be either a string or an integer in /home/polysly9/public_html/studiobijou/wp-includes/category-template.php on line 181

Anyone able to help with this?

bump

This problem has a solution:

https://commonsense360.com/?p=14

From the MistyLook support site:

“You are using WordPress 2.3.1 and MistyLook 3.2. They don’t cooperate together.
Please, download the newest version of ML (3.5) which works with new features WP 2.3.1 offers.”