Versuchen Sie stattdessen dies
$this->coordinates = new CDbExpression("GeomFromText(:point)",
array(':point'=>'POINT('.$coords['lat'].' '.$coords['lng'].')'));
Versuchen Sie stattdessen dies
$this->coordinates = new CDbExpression("GeomFromText(:point)",
array(':point'=>'POINT('.$coords['lat'].' '.$coords['lng'].')'));