diff --git a/LSL2/STPROC/OBJ_WM_OUT.txt b/LSL2/STPROC/OBJ_WM_OUT.txt
index 28bd7fb..3e6f096 100644
--- a/LSL2/STPROC/OBJ_WM_OUT.txt
+++ b/LSL2/STPROC/OBJ_WM_OUT.txt
@@ -613,9 +613,11 @@ NextOpenSlots:
 		
 		FOR I = 1 TO COUNT(WMOKeys,@VM) + (WMOKeys NE '')
 			CassNo = WMOKeys<1,I>[-1,'B*']
-			LOCATE CassNo IN CassNos BY 'AR' USING @VM SETTING Pos ELSE
-				CassNos = INSERT(CassNos,1,Pos,0,CassNo)
-			END
+			If CassNo NE '' then 
+				LOCATE CassNo IN CassNos BY 'AR' USING @VM SETTING Pos ELSE
+					CassNos = INSERT(CassNos,1,Pos,0,CassNo)
+				END
+			end
 		NEXT I
 		
 	END
@@ -625,7 +627,6 @@ NextOpenSlots:
 	* Start Counting at the last box and work backward
 	
 	FOR I = CassCnt TO 1 STEP -1
-		
 		CassNo      = CassNos<1,I>
 		WMOutRec    = XLATE('WM_Out',WONo:'*':WOStep:'*':CassNo,'','X')
 		SlotCnt     = COUNT(WMOutRec<WM_OUT_SLOT_NO$>,@VM) + (WMOutRec<WM_OUT_SLOT_NO$> NE '')