It's not just you. It was disabled a bit ago because of overload on the server. It's due to be enabled again once they come up with something to correct the problem....most likely more space.
In the meantime, if you're looking for a specific thread there may be a way to get around it. First you need to know what forum the thread is in. Go to that forum. At the bottom of the list of threads, you'll see 3 changable tabs for how to display the threads. If you know who started the thread, the title of it or about when it was posted you can set the criteria to search by that. It'll take a little digging. But, you can still find pretty much anything you need.
One hint is to look at the URL when the results come up. If what you're looking for is half way through the alphabet or a couple years back, you can type in the page numbers to replace what's there and save having to skip only a couple pages at a time. (I go by increments of ten to narrow it down to the general area then go page by page.) So, say you decided to look in tickling discussion and sort by thread title. You're results would be the following URL....
ticklingforum.com/forumdisplay.php?forumid=4&pagenumber=1&sortfield=title&sortorder=desc&daysprune=1000&x=15&y=9 (I cut off the
http://www. in order to let the entire addy show.)
If you look at the addy, you'll see
pagenumber= about half way through. That's where you'll be changing page numbers. I know it's not as quick and easy as the regular search funtion. But, it's a way to find things until search is reenabled.
Hope this helps!
Ann