ok then,using your batch, Ill colour code my changes
@echo off
REM %1 is a special variable, the first parameter passed
REM test if any parameter was supplied
If [%1]==[] Goto Error
REM OK, the ~ char in %~1 means strip off the quotes
RENAME "%~1\*.xml" *.sst
GoTo :EOF
REM no param, show error message
:Error
Echo Supply a directory name on the command line, eg
REM %0 is the name of the batchfile as entered on the command line
Echo %0 "My Folder"