Getting this error: blockUI requires jQuery v1.2.3 or later! ?
I saw that many people have been having some issues with jQuery.BlockUI versions after upgrading to a newer WordPress version.
This is NOT a WordPress problem – WordPress merely uses the latest version of jQuery. Previous versions up to 1.9 would obviously pass the buggy test in jQuery.BlockUI code.
Dirty hack without install any plugins, or changing any file, change version in jquery.js in wp-includes/js/jquery/jquery.js to 1.3.2 or any else up to 1.9.9.