If one day webfm(a drupal module) starts to mysteriously fail on you with the error you see there, it is likely you added some code somewhere that(i think?) over-rode the default 'action' method.  In my case, i migrated over a few php libraries and added them to our auto_append file(see php.ini).  One of the files I included was something the prior developer made called 'action.php'  'nuff said.