To me this looks like you're running eZ publish under apache in CGI mode. The search in CGI mode is currently broken, but it will be fixed in future releases.
This is a very old thread, but it seems the problem still exists...
My online searches always return "Undefined module: SearchText=..." phpinfo() returns: Server API :CGI
Thanks for the try. But this was not the problem.
The problem is that the search module itself can't be found.
Search works well on my test environment where I run the same eZ installation, but not on my provider's server.
Please try search on http://ez.lbm-services.de Any help appreciated.
This is most likely since the live server uses cgi / fascgi instead of php as a apache module. You can fix it like descibed above (change get to post) or if your running in virualhost mode it should also help if you set ForceVirtualHost=true in site.ini.
First it had no effect, because I replaced every method=get with method=post.
But the form tag in default pagelayout.tpl has no method defined at all. This has to be completed so that it reads