@Dan Munns from my experience, this error message comes from a missing value for the attribute <name> against the account <USERNAME> in your AD. Double check the profile on the active directory or run the LDAP query of the import setup to make sure some value is returned for the field you mapped to the attribute <name> (which is very likely Distinguished name).
Last time I had this error message, it was because the AD Account was setup with a distinguished name of "BA"... So Hornbill would not allow that.