Steven,
Sorry for the delayed response. I just got into your site to test a little more. Here are the steps I took:
1) I registered with Twitter on the front-end
2) I activated my account
3)
I logged out of the front-end
4) In the admin area, I created a new Channel for Twitter "SourceCoast Test Twitter"
5) I clicked "Save" and then set the user to the account I just created
6) On the front-end, I tried to login with Twitter again.
7) I got the first standard "Authorize App" prompt for read permission.

I was then redirected back to twitter for the 'write' permission, as expected.
However, at this point, I ran into an issue with JFBConnect where there was a blank white page. This is an error that needs a minor code change to fix. If you're up for it, please
this post
.
It doesn't sound like you made it to the white page issue I mentioned above. The only reason I can guess is because you created the Twitter Channel before you authenticated via Twitter with that user. In that case, it's possible JFBConnect isn't setting up the user permission for that user properly.
What I would recommend, just to make sure, is:
* Delete the channel you've created.
* Re-create the channel and set the same user as the 'owner'
* Then, try to authenticate on the front-end.
Hopefully, that gets you going. Not sure what else could be going on as it *seems* like things are right, outside of the error I mentioned above.
Definitely keep me posted on what you find, and good luck!
Alex