To resolve this, you need to change in 'application\models\question.php' the word group by [group] when it is being used to form an SQL statement.

For example on line 966:
$criteria->with = array('group' => array('alias' => 'g'), 'questionL10ns'=>array('alias'=>'ql10n', 'condition'=>"language='".$this->survey->language."'"));

You should change it to:
$criteria->with = array('[group]' => array('alias' => 'g'), 'questionL10ns'=>array('alias'=>'ql10n', 'condition'=>"language='".$this->survey->language."'"));

There were more cases in the code but I don't remember them anymore, and I no longer have this installation on my server.

I'm sorry.

To resolve this, you need to change in 'application\models\question.php' the word group by [group] when it is being used to form an SQL statement.

It must have a Yii gloval solution, because we don't have to use it like this.

My opinon : we must use relations

@c_schmitz, can you please take a look at this one?