Diagnosis
You have tried to post to an asset by entering acredit posting key and a retirement transaction type in the footer.However, it is not possible to post retirements in this way.

Procedure
If you are dealing with a retirement with revenue, then you can startthe retirement by selecting the field 'Asset retirement' in the revenueaccount screen. For a retirement without revenue, choose in theAsset Accounting menu -> "Postings" -> "Ast. Ret. by scrapping".