Index: applications/viewer/jmapviewer/src/org/openstreetmap/gui/jmapviewer/tilesources/AbstractTMSTileSource.java
===================================================================
--- applications/viewer/jmapviewer/src/org/openstreetmap/gui/jmapviewer/tilesources/AbstractTMSTileSource.java	(revision 31132)
+++ applications/viewer/jmapviewer/src/org/openstreetmap/gui/jmapviewer/tilesources/AbstractTMSTileSource.java	(revision 31133)
@@ -135,5 +135,5 @@
     @Override
     public boolean isNoTileAtZoom(Map<String, List<String>> headers, int statusCode, byte[] content) {
-        if(noTileHeaders != null) {
+        if (noTileHeaders != null && headers != null) {
             for (Entry<String, String> searchEntry: noTileHeaders.entrySet()) {
                 List<String> headerVals = headers.get(searchEntry.getKey());