diff --git a/postem-app/src/java/org/sakaiproject/tool/postem/CSV.java b/postem-app/src/java/org/sakaiproject/tool/postem/CSV.java
index 8e20c85..8dc83f6 100644
--- a/postem-app/src/java/org/sakaiproject/tool/postem/CSV.java
+++ b/postem-app/src/java/org/sakaiproject/tool/postem/CSV.java
@@ -107,7 +107,9 @@ public class CSV {
 			Iterator citer = ((List) riter.next()).iterator();
 			while (citer.hasNext()) {
 				String current = (String) citer.next();
-				current = current.replaceAll("\"", "\"\"");
+				if (current != null) {
+					current = current.replaceAll("\"", "\"\"");
+				}
 
 				csv.append("\"");
 				csv.append(current);