Solution : https://service.sap.com/sap/support/notes/716915 (SAP Service marketplace login required)
Key words : 
sap web dispatcher permission table flag, application/x-www-form-urlencoded, graphical class maintenance release 6, extended memory areas larger, post/form fields, event flags increased, http data body, function module th_user_info, client server technology, standalone enqueue server
Related Notes : 
       
| 715600 | |
| 715598 | Global deactivation of GZIP compression for HTTP | 
| 715400 | Max. number of memory pipes (MPI) restricted to 4,000 | 
| 715342 | |
| 715045 | Number of event flags increased to 50,000 for Web Dispatcher | 
| 714907 | |
| 713097 | |
| 712664 | Extended memory memory areas larger than 2GB | 
| 711000 | |
| 707543 | |
| 698017 | ICM Patch Collection (6.40) | 
| 71266 | |
| 71255 |