drupal -- Sub Links always appearing expanded

Question

I'm having an issue with my drupal install. All the sublinks are appearing expanded and there is no option to collapse them. This is causing issue with modules (especially the admin menu module) which appears like this whenever loaded.

This also happens for nested menu's in modules like Panels and Views, and in core menu's like the module menu itself, which cannot be collapsed. It is also affecting the way editing rows work, because the drag and drop functionality has been disabled and the row weights now have to be input by value.

Answer 1

Problem Solved. The issue is due to the fact my web host only has PHP 5.2.17 installed. Works perfectly on PHP 5.3+