this should fix the bug on windows

src/common/optparser.py

@@ -88,10 +88,20 @@ class OptionsParser:
 			fd.close()
 			return err_str
 		fd.close()
+		if os.path.exists(self.__filename):
+			try:
+				os.remove(self.__filename)
+			except:
+				pass
 		try:
 			os.rename(self.__tempfile, self.__filename)
-		except:
-			err_str = _('Unable to open %s for writing\n') % (self.__filename)
+		except Exception, e:
+			err_str = _('Unable to open %s for writing.\n') % (self.__filename)
+			# write the exception in case the bug continue to exists on
+			# windows
+			# TODO remove the following 2 lines
+			from sys import stderr
+			stderr.write(err_str + str(e) + '\n')
 			return err_str
 		return None