The form here seems ok to me, but depending on how your search is setup you may not be triggering it properly. If you can please post back with your results page in a zip archive so that we can take a look at it.
I will check on some things to see if the triggers match up and try to determine why you are not getting the search to work.
Also, do you have a search form anywhere on the site that is working? If so please post back with this as well in a zip archive.