I am having the same problem. I upgraded from 3.6.8 to 3.7.3 and now the shoutbox won't load and I can't post anything. I get the error
When it was running the install.php script everything went fine until the end. It said it had finished and I was happy, but then I didn't know if I should just close the window or click the button that was there that said "continue", so I clicked continue, and it started to reinstall again. At that point I closed the window and checked the site and found these problems.
I inactivated my plugins by unchecking the active boxes in the control panel and still have the same errors.
Any advice would be welcome.