Diagnosis
You want to link the document to another SAP object.
Settings in Customizing (Object links) are used to define which objectlinks are supported for each document type. No entries have been madefor the document type you chose.

Procedure
If you want to link documents of the document type you chose to otherSAP objects, you must make the relevant entries in Customizing. If youare not authorized to make these entries, contact your system manager.