2011638 - BP integration: Message AM215 and region defined per country

The inbound processing is triggered for an idoc, and it results rejected with status 51 (not posted) or status 52 (not fully posted).
Reviewing the status messages for this idoc (hints for reviewing HRMD idocs in KBA 1917207) you find the following error message:

  Region __ is not defined for country __
  Message  AM215

This problem can also cause the following messages to appear in the idoc:

• Relationship ... will be ignored.
  Message HRALX00_ORG532
• Business partner _________ not created.
  Message HRALX00_ORG179

Business partner integration. Idoc distribution with HRMD_ABA message type.

STATE  LAND1 V_T005S , KBA , BC-BMT-OM-ALE , HRMD ALE Distribution , BC-BMT-OM-EBP , HR-SRM ALE, BP & Organizational Management , BC-BMT-OM-CRM , HR-CRM ALE, BP & Organizational Management , How To