We've had to disable searching to keep the servers from catching fire. We'll turn it back on as soon as we can, but it'll probably be a few more days before we do.
You can always use a Google site search.
Just head to google.com, type in what you want to look for, and append "site:http://paizo.com/paizo/messageboards/paizoPublishing/olderProducts/du ngeon/shackledCity" to the end of your query.
Searching has been turned back on, with a couple of tweaks. If it looks like your search will take more than a couple seconds to complete, you'll see a "please wait, searching..." page. That page will automatically refresh every ten seconds until your search is done.