I was publishing via Expressions Web using FPSE earlier this morning. Now, it won't accept my credentials. I've tried to set it up using FTP, but the software crashes. Nonetheless, I tried reinstalling via the Control Panel, but that didn't do anything.

The Front Page Extensions can take fifteen minutes or more to reinstall, did you try again later?
I tested the extensions on your package today with Front Page, and they are working.

Also, when you publish using FTP, be sure to set the default folder to /htdocs. If Expressions tries publishing to the root, it will get permission denied and could crash if the error isn't handled properly.