[Tom Bunch]

I'm not sure I can spot the issue you are both having directly, but maybe I can inundate you with a wall of helpful information.

The CalDAV account configuration itself is about getting OmniPlan to connect to the server, but _not_ to point to specific calendars. You specify a user and password, but this user does not necessarily correspond to any resource in your project. Typically you should omit the path to any calendars as well as the scheme from the server url (i.e. nothing in the "Server address:" field but "cal.example.com"). If you specify a scheme (http: or webcal:) you will probably get "unsupported URL". Of course you'll need to be sure that use are using the correct port and "SSL" setting.

When you use the account in publishing, resources in your project plan will be mapped to what CalDAV calls "principals" by email address. Matching email address must therefore be set up in both places.

Hope that's enough to get you moving along.

-Tom