Solution : https://service.sap.com/sap/support/notes/1312142 (SAP Service marketplace login required)
Summary : 
      During data transfers in Unicode systems using reports RFKKZE00 and RFKKRL00, the runtime error CONVT_CODEPAGE caused by a codepage conversion issue occurs. This is due to a program error. The solution involves implementing advance corrections detailed in the SAP Note. Post-implementation, setting user parameter 80NUNI to 'X' is advised to handle Unicode and non-Unicode data transfers effectively. This parameter ensures appropriate visibility and usability in data transfers. Update necessary text symbols and selection texts as per guidance for correct Unicode handling.
Key words : 
software component   fi-ca                          fi contract acc, terms fp-dtrans, runtime error convt_codepage, manual post-implement, user parameter 80nuni, -unicode data transfer, parameter 80nuni, data transfer, program error, solution implement
Related Notes : 
       
| 1418721 | RFKKCOPM: Runtime error CONVT_CODEPAGE | 
| 1341567 | FPB17: Runtime error CONVT_CODEPAGE | 
| 752859 | sapiconv - a tool for converting the encoding of files | 
| 752835 | Usage of the file interfaces in Unicode systems | 
| 747615 | Tool for converting files from one code page to another |