Ah, thanks for the info.

Don't know if this has any relevancy here, but I'll mention it anyway - I had trouble sending, or even previewing, a PM about 2am GMT last night. My browser (Opera) reported this error:

Not Acceptable

An appropriate representation of the requested resource /vb/private.php could not be found on this server.
It showed up when I tried to preview the message and when I tried to send it without preview. Problem lasted a few minutes, but seemed to resolve itself.