REP-1950 Invalid Source specified.

solution:

source destination need to be correct and valid.

example:
-------------------------------------------------

REM WINDOWS COMPILE REPORT
::compile_report.bat
cls
Echo compiling Report .....
rem ---------------------------
rem begin command line argument
rem ---------------------------
for %%f IN (*.RDF) do rwconverter userid=islbas/islbas@beftn batch=yes source=%%f stype=rdffile DTYPE=repFILE compile_all=yes OVERWRITE=yes logfile=log.txt dest='D:\ISLBAS\Report\des\%%f'
rem -------------------------
rem end command line argument
rem -------------------------
ECHO FINISHED COMPILING

-----------------------------------
Here source need to place in single line

Be Careful: ALL command Line Argument
need to write in a single line.