droplet and search . Using search droplets don't work

[kdb]

Example: www.tvwehen.de
 In any page of the website my droplets [[Laufende_Kurse?format=2]] and [[Nächster_Kurs?format=2]]
work well and return right results. But within the search page there is no result !?
The result is independent of the version of the droplet-module.
Running on a local Acpache xampp server it works well.Problems appear on 1&1 Internet Server.
Thanks for information

Here the code

regarding the post to publish the code I tested again.
the code
$antwort="Hallo Welt";
return $antwort;
results in the same error !!  That meas, that the search modul seems to block interpreting the dorplets !

SOLVED !! 
The problem results in trying to use an undefined object in the search mdoule

[crnogorac081]

You should post a droplet code so we can take a look