diff --git a/LSL2/STPROC/LABELING_SERVICES.txt b/LSL2/STPROC/LABELING_SERVICES.txt
index 2ec3818..2192c2a 100644
--- a/LSL2/STPROC/LABELING_SERVICES.txt
+++ b/LSL2/STPROC/LABELING_SERVICES.txt
@@ -187,7 +187,7 @@ end service
 
 
 Service PrintReactorLabel(ReactNo, LoadLockSide=LOAD_LOCK_SIDE)
-	
+
 	If ( (ReactNo NE '') and (LoadLockSide NE '') ) then
 		BaseZpl            = '^XA^LH10,10^FO70,20^BY2^B3N,,80,N^FD10SR{ReactNo}.{LoadLockSidePrefix}^FS^FO10,120^A045,90^FB400,1,,C^FDR{ReactNo} {LoadLockSide}^FS^XZ'			
 		Convert 'R' to '' in ReactNo
@@ -211,7 +211,10 @@ Service PrintReactorLabel(ReactNo, LoadLockSide=LOAD_LOCK_SIDE)
 			Swap '{LoadLockSide}' with LoadLockSide in Zpl
 		end
 		Labeling_Services('PrintLabel', Zpl, '\\messp1003.infineon.com\MESZBRPRT008')
+	end else
+		Error_Services('Add', 'Error in ':Service:' service. Null ReactNo or LoadLockSide passed in.')
 	end
 	
 end service
 
+
diff --git a/LSL2/STPROC/NDW_PRINT_REACTOR_LABELS_EVENTS.txt b/LSL2/STPROC/NDW_PRINT_REACTOR_LABELS_EVENTS.txt
index c05ef40..51b5553 100644
--- a/LSL2/STPROC/NDW_PRINT_REACTOR_LABELS_EVENTS.txt
+++ b/LSL2/STPROC/NDW_PRINT_REACTOR_LABELS_EVENTS.txt
@@ -78,7 +78,7 @@ Event PUB_PRINT.CLICK()
 	
 	ReactNo = Get_Property(@Window:'.COB_REACTOR', 'TEXT')
 	LLSide  = Get_Property(@Window:'.COB_LOAD_LOCK_SIDE', 'TEXT')
-	Labeling_Services('PrintReactorLabel', ReactNo, LoadLockSide)
+	Labeling_Services('PrintReactorLabel', ReactNo, LLSide)
 	If Error_Services('HasError') then Error_Services('DisplayError')
 	
 end event
@@ -95,3 +95,4 @@ EnablePrintButton:
 	
 return
 
+