<blockquote> file-storage is mounted at file-storage?
</blockquote>
Yes.
<blockquote> Check under yoursite/webdav-support/ to make sure the folder is enabled
</blockquote>
It was enabled by default.
<blockquote> Check in the error log to make sure the filters are loaded.
</blockquote>
Notice: OACS-DAV preauth filters loaded on /dav*
<blockquote> Make sure the registered procedures for oacs-dav are loaded.
</blockquote>
I see "loading" and "loaded" messages for oacs-dav-procs.tcl and oacs-dav-init.tcl in the logs.
What else can I check for?