--- src/alt/java/io/FileImpl.java.orig	2007-12-29 07:19:46.000000000 +0100
+++ src/alt/java/io/FileImpl.java	2007-12-29 07:21:01.000000000 +0100
@@ -171,7 +171,11 @@
     }
 
     public int compareTo(Object o) {
-        return file.compareTo(o);
+        if (!(o instanceof java.io.File)) {
+            return -1;
+        }
+
+        return file.compareTo((java.io.File) o);
     }
 
     public java.io.File getRealFile() {