diff --git a/PROMS/VEPROMS.CSLA.Library/Config/ROFSTLookup.cs b/PROMS/VEPROMS.CSLA.Library/Config/ROFSTLookup.cs
index da116eb5..05312cb6 100644
--- a/PROMS/VEPROMS.CSLA.Library/Config/ROFSTLookup.cs
+++ b/PROMS/VEPROMS.CSLA.Library/Config/ROFSTLookup.cs
@@ -304,13 +304,15 @@ namespace VEPROMS.CSLA.Library
 		public string GetParentChildROValue(rochild roc)
 		{
 			string roval = roc.value;
+			// B2021-093 Don't look for child RO values if "roval" is null
+			if (roval == null) return null;
 			// get the child (slave) information and set the rtnchld.value to the corresponding RO Value
 			int selChldIdx = MyDocVersionInfo.DocVersionConfig.SelectedSlave;
 			string childName = MyDocVersionInfo.DocVersionConfig.Unit_Name; 
 			string aplString = roval;
 			string ChldValue = "";
 			// if the RO Value contains Parent/Child values, parse out default value and the child (slave or unit specific) value
-			while (roval.Contains("<APL DefaultVal="))
+			while (roval != null && roval.Contains("<APL DefaultVal="))
 			{
 				int startCVIdx = roval.IndexOf("<APL DefaultVal=");
 				int EndCVidx = roval.IndexOf(" /APL>", startCVIdx);