Delete Lockfile + cannot edit

Hi Xerte v3.10 upgrade recently announced (I can only assume this is the issue). Now, all projects will play but all give a 'Delete Lockfile' message on attempting to edit and, once clicked (to verify that I'm not working on the same project on a different computer), load a completely blank page.

All content currently impossible to edit. I have 735 students all using Xerte as an assessed component of my course and the snowball of emailing me to ask for help has just overwhelmed me. I don't know what to do.

So, can anyone help? A little desperate here.

So, I assume you upgrade your install. Did you run the database upgrade script?

<url of your xerte install>/upgrade.php

Thank you - I personally did not upgrade it, it was done in the UK, I just use it. If this was not done, would that explain the problem?

Thank you for your help - apparently this was done.

Oddly, I now have functionality back (though the reason for this remains obscure) - it seemed that being able to edit an old project with almost no content cascaded the ability to edit the ones I was desperate to edit. I apologize for wasting your time on this.

In genereal this causes blank screens yes. But I am glad it is sorted now.