Apologies for those database errors just now, I think I've got a handle on what the problem was.
We've recently done a slight server upgrade, but this introduced a few new issues, but I think I've got them now.
It would be a great help if you get the database error screen to go to View -> Page Source (that's what it is on Firefox, Tools button and View Source on others I think) and get the exact error message from there and PM or VM it to me. It is in a bit of commented out HTML, which is in green, just copy the lot if you aren't sure. Might need to wrap it in code tags to let you send it (as VB won't let you post HTML).
Also, if it is a while after the event, put the time in as well.
The more info I can get on the server issues the more reliable it can be made.