Based on reports from MF, I checked various domain names:

1) I went to these two URLS:
http://mysterescanadiens.ca
http://www.mysterescanadiens.ca
If I do nothing on that page for a little while, it automatically loads the page:
http://www.mysterescanadiens.ca/mysteries/indexfr.html
which is the same page as
http://www.canadianmysteries.ca/mysteries/indexfr.html
So, those domain names appear to be working properly.

2) The URL www.cybermysteres.ca automatically redirects to the page http://www.mysteryquests.ca/indexen.html but the URL box does not change. This is weird and must be something that the ISP is doing.

First, the URL www.cybermysteres.ca should point to http://www.cybermysteres.ca/indexfr.html. Second, if you type in the URL http://www.cybermysteres.ca/indexfr.html, you get a "page not found" error. What you should see is the page you see if you use the URL http://www.mysteryquests.ca/indexfr.html

The URL http://www.mysteryquests.ca/ automatically redirects to the page http://www.mysteryquests.ca/indexen.html, which is sensible behaviour. On that page, the link on Français links to http://www.mysteryquests.ca/indexfr.html and that works. I created a link on FR, which links to http://www.cybermysteres.ca/indexfr.html and that link fails.

Got contact info for hosting company from MF, and notice that actually getting tech support is not easy. Will give it a shot next week.