I have exactly the same issue. I have apache webdav with
authentication on the dav directory. This all worked perfectly fine on
lightning 0.3x. I have also seen some 401/404 errors in my logs. Not
sure how to go about fixing this.
The release notes state:
> If you are using Apache Limit or LimitExcept directives you may
> get 401 errors when modifying events unless you make sure that
> GET, HEAD, OPTIONS and PROPFIND are not limited. e.g.
> <LimitExcept GET HEAD OPTIONS PROPFIND>" (bug 380291)
[http://www.mozilla.org/projects/calendar/releases/common0.5.html]
Maybe you see this issue?
/Stefan