WordPress MU

Everything was working fine and 2 days ago categories just disappeared from the admin panel and the website. We didn't change anything on the site so it happened by itself. When i uncomment this line in the taxonomy.php it prints them out for the website not the admin panel in an unordered position. This is on line 651.
Website address:
http://www.ecasebriefs.com/
Category view:
http://www.ecasebriefs.com/blog/category/law/
If you click one of the tabs on the left side you will see the hierarchy. even though under categories just comes after the first 16 main ones.

if ( $child_of ) {
$hierarchy = _get_term_hierarchy($taxonomies[0]);
if ( !isset($hierarchy[$child_of]) )
{
// return $empty_array;
}
}

Assuming that the files have not changed, I can only assume that there is an issue with the database.

Have you attempted to disable all plugins and use a default them to replicate the issue? 90% of the time that seems to give me direction.

Eric

We found out that our CPU was working at 85-90 percent and same as our ram and actually thought that might be the reason. The hosting company is upgrading our server. If it still persists I will try your suggestion.

Thank you btw

It turned out it was a memory issue on the server. Both the CPU and the RAM were too low so it was crashing when the categories were being sorted. For a somewhat solution i commented line 651 version 2.8.4 wpmu. It was just not working properly but i was still getting the categories printed.

if ( $child_of ) {
		$hierarchy = _get_term_hierarchy($taxonomies[0]);
		if ( !isset($hierarchy[$child_of]) )
		{
			//	return $empty_array;
		}
	}