Codeception/Codeception — pull request #750 by FnTm (2013-12-11 09:56:21+00:00)
Title: Fixed a bug, where passing numbers as values to submitForm() would cause an error in the \WebDriver. Fixes #749

This does fix my problem, but I am not sure, whether or not it will fix it there is a multidimsional array passed to submitForm().