With which version of Blender, which version of the Blender Source Tools, and which .blend file?

There is a corrupt Unicode character in your SMD file. There's nothing the Blender Source Tools can do about this. The data isn't there.

Sounds like a corrupt Blender installation. The typing module should be there.

This was fixed in 3.4.1. You need to update Blender, then update the addon.

Yes, I would still like the DMX file.

Source Filmmaker has a different animation format from the animations that you compile into a model for use in a normal Source game.

However, this is a DMX parsing error, and that at least should work. Please upload the DMX file you are trying to import.

You need to download an older version of the add-on from http://steamreview.org/BlenderSourceTools/archives/

You need to use at least Blender 4.1.

I think the best thing for you to do is download the addon from the GitHub repo at https://github.com/Artfunkel/BlenderSourceTools/tags

The site doesn't have a certificate of it's own, and all links to it are http. I've noticed that if you nevertheless visit it with https you now get a certificate from my webhost's FTP server (kasserver.com), which may or may not be something I can configure. It's possibly related to my email server.