Les,
I do not think so. I am testing it. I think the batch file should be tested for existence of %2
Code:

If NOT @LOGONMODE
	Break ON
EndIf
Dim $SO
$SO = SetOption("Explicit","On")
$SO = SetOption("NoMacrosInStrings","On")
$SO = SetOption("NoVarsInStrings","On")
$SO = SetOption("WrapAtEOL","On")

If IsDeclared($client)
	If CheckClient ($Client) = 1
		? "ClientOK" ?
	Else
		? "ErrorMessage" ?
	EndIf
EndIf

Function CheckClient ($ClientColor)
	Select
		Case $ClientColor="Oranje"
			$CheckClient=1
		Case $ClientColor="Groen"
			$CheckClient=2;ABS(1-(InGroup("\\" + @WKSTA + "\Administrators")))
		Case 1
			$CheckClient=0
	EndSelect
EndFunction

Code:

@echo off
REM echo parm0 = %0
REM echo parm1 = %1
REM echo parm2 = %2
REM echo parm3 = %3
REM echo parm4 = %4
REM echo parm5 = %5
REM echo parm6 = %6
REM echo parm7 = %7
REM echo parm8 = %8
REM echo parm9 = %9
If !%2 == ! GoTo end
..\..\kix32.exe test.kix $KG=%1 $CLIENT=%2
:end