Bad arguments in implode function

I am getting this error message:

warning: implode() [function.implode]: Bad arguments. in [drupal directory]\sites\all\modules\subform_element\subform_element.module on line 211.

I am using this module as a dependency for the AddNode module. This error message occurs in a couple of places:

1. When I create content where the content type includes an AddNode field.
2. When I configure the AddNode field.