Problem: you are trying to create an Activity Allocation document in ERP from your application.

Solution: There are two possibilities.

First – you can create a Batch Input for transaction KB21N and by this create the documents.

Second – better solution – you can use BAPI FM called BAPI_ACC_ACTIVITY_ALLOC_POST. This FM will allow you to create new Activity Allocation documents with easy FM module call. It will also return all messages that the standard transaction returns.

Remember to put a user name into the doc_header-username field, otherwise BAPI will return error.