Solution : https://service.sap.com/sap/support/notes/132631 (SAP Service marketplace login required)
Key words : 
repeatedly occuring database errors ora1555, additional key words emu, img point 'start conversion', document conversion program rfewudoc, expect considerable performance losses, logical errors refer, = red traffic light, 0f apply crt 91, customer-defined tables, terminated program starts
Related Notes : 
       
| 393505 | Cluster: Collective note Basis cluster technique | 
| 356648 | EURO: Restartability for cluster technique | 
| 183158 | LC changeover to euro: Cluster functions | 
| 157704 | Change dayl. sav.time/std.time and loc.crcy chang. | 
| 128965 | |
| 121245 | System settings for local currency changeover to euro | 
| 114856 | Euro changeover:Restart capability of spec. progrms |