Bei Abfrage einer Variablen Absturz des Batchs

echo Copy WinXP-Files!
echo Copy WinXP-Files! >> C:\Log.txt

if exist "C:\INSTALL\i386" goto available_win  
nircmd.exe cdrom open D: 
:beg_win
echo Please insert the Windows XP Prof. Disc and press a key!

If not Exist "D:\i386" goto sta_win  
xcopy "D:\" "C:\INSTALL\i386\" /E /V /H  
if errorlevel 0 goto success_win else goto error_win

:error_win
echo Copying of the XP files was not successful! %date% %time% >> C:\Log.txt
echo Copying of the XP files was not successful!
goto end_win

:available_win
echo Copying of the Windows files was omitted because the listing already exists! %date% %time% >> C:\Log.txt
echo Copying of the Windows files was omitted because the listing already exists!
goto end_win

:sta_win
echo Please put in the right Windows XP Prof. Disc! %date% %time% >> C:\Log.txt
echo Please put in the right Windows XP Prof. Disc!
set /p WIN=If you want to repeat the copying, press "y", if you want to continue without copying the files press "n" and "Enter"!  
If %WIN%==n goto error_win
If %WIN%==y goto beg_win
echo The key you typed in was wrong! Please enter a correct one!
goto sta_win


:success_win 
echo Copying of the XP files was successful! %date% %time% >> C:\Log.txt
echo Copying of the XP files was successful!

:end_win