I have activated the API at basecamp, followed several different sets of directions which I found scattered on the internet, and no joy.

One set said to login using the info as if I were on a browser. So I entered that info on a test login.

One set said to enter my token for feedreaders. So I did that, with a token for username and an x for password. I tried it with my actual password.
then I tried it using my token for iCal (just in case I misunderstood!)

I tried it with and without the 's' in https
I forget what else I have tried.
i can login with no trouble on the website with the browser.

on Sherpa I get an error no matter what combo I have tried:
Connection Failure
You have either entered the incorrect user name/password or Base camp url for this account