diff --git a/batik-css/src/main/java/org/apache/batik/css/engine/CSSEngine.java b/batik-css/src/main/java/org/apache/batik/css/engine/CSSEngine.java
index 8483a408eb..62c2a602e9 100644
--- a/batik-css/src/main/java/org/apache/batik/css/engine/CSSEngine.java
+++ b/batik-css/src/main/java/org/apache/batik/css/engine/CSSEngine.java
@@ -1220,9 +1220,10 @@ public void parseStyleSheet(StyleSheet ss,
             // e.printStackTrace();
             String m = e.getMessage();
             if (m == null) m = "";
+            String u = uri == null ? "<unknown>" : uri.toString(); 
             String s = Messages.formatMessage
                 ("stylesheet.syntax.error",
-                 new Object[] { uri.toString(), rules, m });
+                 new Object[] {u , rules, m });
             DOMException de = new DOMException(DOMException.SYNTAX_ERR, s);
             if (userAgent == null) throw de;
             userAgent.displayError(de);