Diagnosis
You attempted to make an entry for an external transaction. Differententries are available for the statistics key and/or the debit/creditindicator for this transaction in Customizing.

Procedure
Change the Customizing appropriately and make the entry again.
Maintain Transactions for Industry-SpecificComponent for Media
Maintian Transactions Industry-SpecificComponent Telecommunications
Maintain Transactions for IS-U/IS-T