I installed this module and visited admin/build/simpletest_automator/add. I filled in the form, and I get returned to the same page. Nothing gets added to the list and no error message appears except the warning:

Warning: array_merge(): Argument #1 is not an array in _form_set_class() (line 4215 of /path/to/drupal/includes/form.inc).

I've tried this with and without javascript enabled.