Index: trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java	(revision 19290)
+++ trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java	(revision 19291)
@@ -293,5 +293,5 @@
 
         try {
-            if ("file".equalsIgnoreCase(new URI(tileSource.getBaseUrl()).toURL().getProtocol())) {
+            if (tileSource.getBaseUrl() != null && "file".equalsIgnoreCase(new URI(tileSource.getBaseUrl()).toURL().getProtocol())) {
                 tileLoader = new OsmTileLoader(this);
             }