The UE server behavior on the page looks like it is being triggered on 'before page load'. How are you accessing the page? What happens if you continue to let it load? Also do you have your error reporting turned on in php? If not you should enable this to see any errors that might be occurring.
Are you able to add any server behaviors to any pages? What results do you get with other php pages with different server behaviors on them?
It is very unusual to have a script on a page and have nothing occur as a result so I'm asking for this info to see what type of an issue this might be. If you need to add code to the pages to enable error reporting you can add this to the top of your pages to turn it on: