Adding/Importing User to Org Issues

Hello, I am attemping to import a user from LDAP using the SDK, then share a vApp with that user.  I am trying to adapt the sample code which demonstrates how to add a user to do this.

First of all, using the sample code as is to simply add a user is throwing the following exception at the AdminOrganization.CreateUser(UserType userType) call:

Unexpected error. Model object must be an OrganizationUser object  - Model object must be an OrganizationUser object

I do not understand what an OrganizationUser object is.