SAP Note 11324 - Cancellation when creating/changing/displaying PReq.

Symptom

Cancellation in network/order when adding an externally processed
operation or directly procured component.

Cause and prerequisites

There may be a missing authorization for either purchasing group,
plant or purchasing organization.

Solution
Include authorizations for the authorization objects in the
authorization profile of the user:
M_BANF_EKO : for the purchasing organization
M_BANF_EKG : for the purchasing group
M_BANF_WRK : for the plant
(possibly authorization '*' - all values).

Key word: PReq