Try using a dummy account. Remember that Kobo does not check the account for validity so
ima.pseudonym@nehwon.org as an example will be accepted.
Have you tried using the
One-Click Install Packages for KOReader & Plato thread in the Kobo Developer's forum. It will install NickelMenu and KFMON as well as your choice of KOReader and/or Plato. Using the install scripts in the 2nd message in the thread does a very decent job of automating the procedure.