The server appears fine, and the log files don't show any connections from your host for the last 24hours.
However, I've just checked the URL you gave and I was able to recieve a valid quote on the *one* product item I tested with. This also produced an entry in the log file.
So, your problem is either related to a specific product (or products), OR I'm suspecting that since you have changed nothing, and we've changed nothing, then your webhost must have changed something. If this is the case, it looks like they've changed it back.
Cheers
Rod
Bookmarks