Solution : https://service.sap.com/sap/support/notes/1265976 (SAP Service marketplace login required)
Key words : 
attached correction instructions, webdynpro applications, maintain substitute, maintain substitutes, selected manager, requisition manager, feedback questionnaire, relevant window, system displays, empty page
Related Notes : 
       
| 1156407 | SAP ERP Enhan.Pk.4 SP Stack 01(11/2008) - Release Info. Note |