Resource types

I am experiencing a similar problem. When I select "Link to file or web site" on the drop down menu I get a page saying Error, This module type doesn't exist. When I click continue I am taken back to the home page. It was working on Friday when I left the office and I don't believe any changes have been made since then as I am the only administrator. In the configurartion under modules it lists resource as a module and all of the settings seem to be as they were before. It says I have 391 resources and that it is version number 2005041100. I would appreciate any thoughts. If you need any further information Please ask. Many Thanks in advance. Chris