[megaloman]

Код:

@Echo Off
cls
	Set "BoxIn=Z:\Box_In\infile.txt"
	Set "BoxOut=Z:\Box_Out"
	Set "Delim=O"

	Set "OutFile=Err.txt"
	FOR /F "usebackq delims=" %%i IN ("%BoxIn%") DO Call :Out "%BoxOut%" "%%i"
pause
Exit /B 0

:Out
	Set "Str=%~2"
	If "%Str:~0,1%"=="%Delim%" FOR /F "delims=(" %%j IN ("%Str%") DO (
		Set "OutFile=%%j"
		2>nul Del "%~1\%%j"
	)
	>>"%~1\%OutFile%" Echo %~2
Exit /B 0