Path Auto throws an error on node submit if it contains no datefield...

It complains about the second arg to format date... see attached patch which checks if the node has a date field before even trying to load data from it...

You could probably drop the top half of that function and just have the foreach(content_field() as $field) since it looks like this... see example second patch attached that should perform a better job at the gig, but I dont' have time to test it currenlty.