diff --git a/common/content/io.js b/common/content/io.js
index 6ad268bc..e63b3849 100644
--- a/common/content/io.js
+++ b/common/content/io.js
@@ -118,9 +118,16 @@ function IO() //{{{
     function joinPaths(head, tail)
     {
         let path = ioManager.getFile(head);
-        path.appendRelativePath(ioManager.expandPath(tail)); // FIXME: should only expand env vars and normalise path separators
-        if (path.exists())
-            path.normalize();
+        try
+        {
+            path.appendRelativePath(ioManager.expandPath(tail)); // FIXME: should only expand env vars and normalise path separators
+            if (path.exists())
+                path.normalize();
+        }
+        catch(e)
+        {
+            return { exists: function () false };
+        }
         return path;
     }
 
@@ -943,7 +950,7 @@ lookup:
 
                 liberator.echomsg("finished sourcing " + filename.quote(), 2);
 
-                liberator.log("Sourced: " + file.path, 3);
+                liberator.log("Sourced: " + filename, 3);
             }
             catch (e)
             {
diff --git a/common/content/options.js b/common/content/options.js
index 2dfb7e63..353bf5bf 100644
--- a/common/content/options.js
+++ b/common/content/options.js
@@ -683,7 +683,7 @@ function Options() //{{{
                         context.completions = [
                                 [loadPreference(filter, null, false), "Current Value"],
                                 [loadPreference(filter, null, true), "Default Value"]
-                        ];
+                        ].filter(function ([k]) k != null);
                         return;
                     }