i am trying to set up Virtualmin but it keeps saying

--------------------------------------------------------------------------------
The status of your system is being checked to ensure that all enabled features are available, that the mail server is properly configurated, and that quotas are active ..


No virtual domains file was found in your Postfix configuration. Maybe no virtual domain map has been defined.


.. your system is not ready for use by Virtualmin.


can any one help

O, I am running webmin 1.16 on mandrake 10.0