Problem using webform conditional and ajax in hook_form_alter

I'm developing a module using hook_form_alter that modifies a webform, when implement ajax and have a webform condition, appears the next error:

Notice: Undefined index: clicked_button en _webform_conditional_get_submitted_values() (línea 296 de C:\wamp\www\mitestsite\sites\all\modules\webform_conditional\webform_conditional.module).
Notice: Undefined index: clicked_button en _webform_conditional_get_submitted_values() (línea 299 de C:\wamp\www\mitestsite\sites\all\modules\webform_conditional\webform_conditional.module).

For see the error, import the node export, and put the example module error in mitestsite\sites\all\modules\
next step active the example module error and go to the form.

Sorry for my english.