Solution : https://service.sap.com/sap/support/notes/686239 (SAP Service marketplace login required)
Key words : 
delete private methodis_active_ace_userfrom class, acd administration tool, inactive user reason, exporting parameterex_is_active_ace_userof type, attached correction instructions, private method, correction instructions, user context, im_user_nameof type, authorization mode
Related Notes : 
       
| 696262 | CRM 4.0 SP Stack 1/2004 (SAPKU40004): Release & Info. Note |