Fatal Error: Call to a member function internalIdentifier() on a non-object

Using the following version of entity API:

; Information added by drupal.org packaging script on 2012-05-11
version = "7.x-1.0-rc2+2-dev"
core = "7.x"
project = "entity"
datestamp = "1336695251"

which is the latest version available from the project page
http://drupal.org/project/entity

I figured out what the problem was:

Here is the code that the error message is referring to:

// set a default state if not provided
    if (!$this->state || $this->state == -1) {
      $default_state = registration_get_default_state();
      $this->state = $default_state->internalIdentifier();
    }

In my registration states settings, there was no default state checked, so when it tried to process the new registration it could not find a default state to apply.

So this isn't a problem with the entity module, maybe that conditional should be written differently or the user should be forced to select a default state.

The reason I wasn't using a default state is because I deactivated all the registration states, since I don't want to use any of them.

at /admin/structure/registration/registration_states

there is an array of check boxes for each state. I just unchecked them all.

The system requires states, they are not optional, and you must have at least one that's set as the default.

I didn't know this. It makes sense though at least internally on the backend. But you don't necessarily want users to see the states.

Also FYI, to fix the error I just checked the "default" box next to the "confirmed" state, but did not check the "active" check box. I'm pretty sure it's applying the default state despite not being "active" since it showed up after submitting a registration.