I have a url containing:
used%2Cnearlynew%2Cnew
it was sent to me in Google Talk, clicking on it there brings it up in Google Chrome perfectly.
if I put that same url into a keynote note, then when I click on it in the browser the address bar shows it as:
used%252Cnearlynew%252Cnew
that is the only difference in the two urls, the latter one then fails on the web server, while the former link still works perfectly