Index: src/org/openstreetmap/josm/io/BoundingBoxDownloader.java
===================================================================
--- src/org/openstreetmap/josm/io/BoundingBoxDownloader.java	(revision 203)
+++ src/org/openstreetmap/josm/io/BoundingBoxDownloader.java	(revision 204)
@@ -66,4 +66,9 @@
     		data.add(list);
     		return data;
+    	} catch (IllegalArgumentException e) {
+    		// caused by HttpUrlConnection in case of illegal stuff in the response
+    		if (cancel)
+    			return null;
+    		throw e;
     	} catch (IOException e) {
     		if (cancel)
Index: src/org/openstreetmap/josm/tools/ImageProvider.java
===================================================================
--- src/org/openstreetmap/josm/tools/ImageProvider.java	(revision 203)
+++ src/org/openstreetmap/josm/tools/ImageProvider.java	(revision 204)
@@ -77,5 +77,5 @@
 		}
 		if (path == null)
-			throw new NullPointerException("/images/"+subdir+name+ext+" not found");
+			return null;
 		Image img = cache.get(path);
 		if (img == null) {