Cannot create new user when nodeprofile is set to be shown during user registration

Fresh install with:
Drupal 5.6
Usernode 5.x-1.3
Nodefamily 5.x-1.3
Subform Element 5.x-1.3

Created a new content type and set it so that its Maximum population is 1 and "Use this content type as a nodeprofile for users" is ticked
On the content type's Node Profile tab, tick "Show this node profile during user registration"

While logged in as admin, I start to create a user. As expected, the new content type's fields appear as part of the user registration process. However when I try to save the user, I get the error "The username sampleuser does not exist."

If I go back to the content type's Node Profile tab and untick "Show this node profile during user registration" then I AM able to create the new user, but of course the nodeprofile fields don't show up. Once the user is created, I can then go back and edit it to fill in the nodeprofile fields of the new content type.

I am not familiar with the code, but from the error message, could it be that the module is trying to create the usernode or the nodeprofile node *before* the user record itself is created?