I created a folder named the hex code of the color, shared it with the email address hidden in the picture, and nothing happened.

Maybe their servers are overloaded?

Definitely didn't include the #. Simply created a folder named 1F75CC, shared it with dropquest@dropbox.com and...nothing. Can't imagine what I'm still doing wrong, so I'm chalking it up to a bug on their end now.

It worked for me. The only thing I did differently was including the contents of the previous zip file (the image and the step21.txt) in the shared folder.

Don't include the # in the beginning.

I did that (shared with myself), but all that happened was that a .dropbox file showed up.

edit: figured it out. Thanks.