How would Zend have anything to do with it? Gazillions of people are working in PHP. Or are you saying it's a PHP bug?
I'd suggest that you time the script. Basically, you record the time at the very head of the document, then at the end and then echo the time it took to parse the page. If that's rediculously long, then start moving the end point up towards the top until you find the culprit. If the parsing of the page only took a few milliseconds, or at least under a second, but you didn't get the page until 20 seconds later or so, it's probably best to contact your admins as it's prob a server side issue. Be sure to check the tracert as well, google will explain what I mean.
I'm sorry, I'm kinda in a rush, I have to fly out to San Jose in a few hours -- I'm here trying to run through all the replies before I start packing, or I'd write something up. I think there's a script in the snippets section that will help.