The option "validation_constraint" does not exist

[Numerah]

when i use this package i got the following error

"at OptionsResolver ->validateOptionsExistence (array('validation_constraint' => object(Collection), 'data' => array('from' => object(DateTime), 'to' => object(DateTime))))
in /vendor/symfony/symfony/src/Symfony/Component/OptionsResolver/OptionsResolver.php at line 224"

i also found the solution that validation constraint should be added on each form element not on builder kindly check

http://stackoverflow.com/questions/18147834/symfony-2-the-option-validation-constraint-does-not-exist