I think I may know what your problem is, as I was just cursing at my browsers for about the past 10 minutes with the same issue.
Are you using a Caching plugin at all for wordpress? Like Wordpress Super Cache, or W3 Cache?
If so, turn the plugin off, or delete the cache and disable caching.
Then once it's off/disabled refresh your site in other browsers. It should work (if caching is the issue)
Worked for me.
Eric, you may want to consider making this thread sticky so everyone can see it. I would guess that it's a common problem among datafeedr users.
Or maybe it has already been address elsewhere. . ? I only searched for 'browser' and didn't look much further.