self.GetExtensionsTxt().SetValue(str(ft.GetExtensions()))
         self.GetDescriptionTxt().SetValue(str(ft.GetDescription()))
 
-        filename = os.path.join("SPAM", ft.GetExtensions()[0])
+        extList = ft.GetExtensions()
+        if extList:
+            ext = extList[0]
+            if ext[0] == ".": ext = ext[1:]
+        else:
+            ext = ""
+        filename = "SPAM" + "." + ext
         mime = ft.GetMimeType() or ""
         cmd = ft.GetOpenCommand(filename, mime)
         self.GetOpenCmdTxt().SetValue(str(cmd))