[Solved] Blank Pages with WordPress 2.6.x

After upgrading to WordPress 2.6 it occasionally happend that an empty page was displayed in the browser when navigating through the blog or working in the admin area. Refreshing the browser using CTRL+F5 usually helped in that case. Today I upgraded to WordPress 2.6.2 and I was not able to access the plug-ins page of the admin area anymore. No matter how often I refreshed the page in the browser it stayed blank.
First I searched the web for possible solutions. I found quite a number of discussions giving tips about this widely known problem but unfortunately none of these solutions helped in my case.
So I again started debugging the WordPress code and finally found the lines of code causing the trouble. The problem are (object) casts in the wp-includes/taxonomy.php file that transform an array into an object:

$wp_taxonomies['category'] = (object) array('name' => 'category', 'object_type' => 'post', 'hierarchical' => true, 'update_count_callback' => '_update_post_term_count');
$wp_taxonomies['post_tag'] = (object) array('name' => 'post_tag', 'object_type' => 'post', 'hierarchical' => false, 'update_count_callback' => '_update_post_term_count');
$wp_taxonomies['link_category'] = (object) array('name' => 'link_category', 'object_type' => 'link', 'hierarchical' => false);

Since I don’t get any error messages neither on the screen nor in the log files I have no idea why these casts fail. The PHP version used to serve the site is the latest stable 5.x release from php.net.
As a workaround I introduced a function that does also transforms an array into an object but does not rely on the casting mechanism.

function arr2obj($arr) {
	foreach ($arr as $k => $v) $obj -> {$k} = $v;
	return $obj;
}

$wp_taxonomies['category'] = arr2obj(array('name' => 'category', 'object_type' => 'post', 'hierarchical' => true, 'update_count_callback' => '_update_post_term_count'));
$wp_taxonomies['post_tag'] = arr2obj(array('name' => 'post_tag', 'object_type' => 'post', 'hierarchical' => false, 'update_count_callback' => '_update_post_term_count'));
$wp_taxonomies['link_category'] = arr2obj(array('name' => 'link_category', 'object_type' => 'link', 'hierarchical' => false));