I resolved the problem in probably the most unorthodox way you'll ever read. LOL
I opened synaptic.
Clicked on "reload".
When the error message opened up,
I highlighted and copied the url given.
Truncated that to just before the name of the mint version.
Pasted that into my browser.
Then looked for the next name up, in the list.
Went back to synaptic.
Clicked on "settings" >repositories >other software
Looked for the same repository as had been in the error message.
Exchanged the name in the respository url, with the one that I had seen at the actual page in the browser.
Kept this up for each repository entry, until I finally stopped getting error messages when I clicked "reload".
I think I ended up with at least three different 'version names', in that list of repositories before they all started playing nicely with each other.
Then I searched for Bibletime again, and there it was! And it installed beautifully.
One thing I really like about this program is that you can search for a specific word or sentence, and find ALL instances of it in the Bible. Gives you a great cross-reference to figure out what something likely really means instead of just what it looks like in the single context.
"The true measure of a man is how he treats someone who can do him absolutely no good." ~Samuel Johnson (1709-1784)