It looks like Thinks.com has changed the URL format for their daily puzzle. If you use the Thinks.com source, you should open it in Preferences and change the URL to:
Unfortunately if you've already tried to download for today, Black Ink will repeatedly try to open the "Bad Puzzle". So you'll want to locate the bad puzzle file and delete it:
[Home] -> Library -> Application Support -> Black Ink -> Puzzles -> Thinks.com Daily
Then retry with the new URL in place, and everything should work again!