No record with the specified key exists on the database. This must be a Informatica Global Customer Support error, unless the user is using unorthodox methods to access the data, and supplying their own key manually.
PowerExchange rejects the registration.
Contact Informatica Global Customer Support for support on which traces are required, or give Informatica Global Customer Support a copy of the database containing the failing registration, along with information on the software level being used.