Help.... My users are getting odd messages for some files in our vault; I've been able to replicate it, but don't understand it.  The files are accessible via the desktop client, it's only the web client that throws the errors:

Except sometimes it throws this instead:

It doesn't matter what I do, or even if I'm logged in as the admin user rather than myself. As I mentioned, I can go to the desktop client (Windows 7 x64) and get all the problem files immediately. I see this happen in Firefox, Safari and Chrome under OSX, and IE under Windows.

Help! How do I fix this? I've done the Google, I've searched the knowledge base and the user forums, and don't find anything.

Thank you,

Ruth