Thanks to Misterhaan and Andrewf. I fixed the errors that you pointed out to me. Thanks so much. I'm still having the same problem, though.
Here's what Dreamhost support has to say:
"This is because your code is not set up to handle the extra data that's being passed by the browser. You'll need to fix the code on your website to get this working as expected. Here's an example of the extra data being passed by the browser:
You need to set up your website's code to be able to accept that, which
it is not."
Any other thoughts? Thanks!