Solution : https://service.sap.com/sap/support/notes/538174 (SAP Service marketplace login required)
Key words : 
area bc-db-db2, database system db2/390, attached advance correction, ibm utilitiy dstats, im transactions, im reporting, performance problems, terms runtime, time_out reason, program error
Related Notes : 
       
| 538907 | CJ30, CJ40: Performance problems under DB2 | 
| 339596 | TIME OUT whn insertng WBS in prjct (ORACLE problem) | 
| 135254 | Perfrmance problems in Projct System as of Rel. 4.0 |