I tried out "support ticket" modul and it seemed to work. It uses coments for communication with support requests.
After deinstalling troubles began.
After deinstallation i have often strange messages:
User warning: The following module is missing from the file system: support in drupal_get_filename() (line 233 of core/includes/bootstrap.inc).
And after installing search api modul, database serach i get following error message after installing moduls: