1800635 - Users cannot be seen in BPC Security in BPC Admin

• Users are not able to see any user in the Security of Planning and Consolidation Administration for any environment.
• When trying to add a new user, users get the error messages:
  "Error occurred while saving the user changes".
  System exception: You are not authorized to assign roles"
• In SLG1 transaction, the following errors can be found:
  "BAPI_USER_GET_DETAIL XXXX USER_NAME
  You are not authorized to display users
  BAPI_USER_ACTGROUPS_DELETE XXXX USER_NAME
  You are not authorized to assign roles to user USER_NAME or to cancel the assignment."
  (where XXXX is the user assigned to BPC RFC Destination)

SAP Business Planning and Consolidation 10 for NetWeaver

KBA , EPM-BPC-NW-ADM-SEC , Security , Problem