Exposure login problem

I just downloaded Exposure for my new iPhone, but I cannot get it to log in. I can log in easily via Safari to flickr.com or to i.flickr.com; but when I try to log in via exposure, I enter the username and password on the Flickr page, and then I get the message: "There was a problem with your authorization of Exposure." It asks me to login again, but then immediately crashes.