Joe Offer wrote: The way I make an internal link is ... href=thread.cfm?threadid=163172>...

That will work in some pages (e.g. a thread) but may not in others (where the page is in a subdirectory

mudcat.org/something/page.cfm

I don't know whether there are any such pages but better to start it with a "/" - e.g. /thread.cfm...

You can probably leave the quotes off the href= if a link contains no spaces, or some other characters, but it's non-standard. A copied URL should not contain spaces - the copy should replace them with %20.