Hi Stefan
There is the following code in application/helpers/remotecontrol/remotecontrol_handle.php in line 140:

// Load default email templates for the chosen language
$oLanguage = new Limesurvey_lang($sSurveyLanguage);
$aDefaultTexts = templateDefaultTexts($oLanguage, 'unescaped');
unset($oLanguage);

The class "Limesurvey_lang" can not be found and variable "$aDefaultTexts" is not used anywhere in the code. So it looks like this part of code is not necessary and it broke "remote control" functionality at the same time.

The functionality works fine if this part of code is removed

@badaboom : yes but survey NEED survey_language_seetings ... else broken survey

You have to pass language. In other case you will get exception
if( $sSurveyTitle=='' || $sSurveyLanguage=='' || !array_key_exists($sSurveyLanguage,getLanguageDataRestricted()) || !in_array($sformat, array('A','G','S')))
return array('status' => 'Faulty parameters');

line 119

So you have to pass language in any way and in this case we don't need default language.
And more: variable "$aDefaultTexts" is not used, so default language is not initialized.

Look at the file application/helpers/remotecontrol/remotecontrol_handle.php :: add_survey function.

I am not a developer of a survey. I had the same problem. I have disabled part of code described in my first comment and it works

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=17116

2.50+ Build 160206 released