Error Creating User

Currently trying to set up a form that will auto create new users using the Active Directory Components withing Workflow.  On filling in all the request user details and clicking create i am constantly getting the error message

"Log Error:
Component Executed: Create User (LogicBase.Components.ActiveDirectory.CreateUserComponent), exit path is 'Error'
Data:
ActiveDirectoryError = "Value cannot be null.
Parameter name: identityValue""

I have looked everywhere and i am unable to find anything that can tell me what this error relates too.