Windows Vista does not ship with dhtmled.ocx and they say that applications that use it should be migrated to use a new HTML editing component,
http://msdn2.microsoft.com/en-us/library/aa663363.aspx
Meanwhile, to get this working on Vista, go and get the redist from Microsoft at;
http://www.microsoft.com/downloads/deta ... laylang=en
Once that is installed, BlogDesk will run... :)