Hi, I'm really glad to have found this module besides using basic tables. I currently have an entity reference that I need to reference a user ID. However, when placing into the field groups table, I get this error:
Notice: Undefined index: target_id in entityreference_field_widget_form()(line 670 of /home/../modules/entityreference/entityreference.module).
Warning: array_flip() [function.array-flip]: Can only flip STRING and INTEGER values! in DrupalDefaultEntityController->load()(line 178 of /home/.../includes/entity.inc).