I've noticed the items being displayed in my instance of River4 were out of date, actually, they are pretty old. I checked the River4 repository on github and saw that v0.94 includes a fix for this problem and I had not been updating my copy or River4 on Heroku.
I couldn't figure out how to update my River4 app on Heroku, and so I decided to consolidate my node.js apps on to my Debian server running at CloudAtCost. The server is already running node and the Fargo Publisher.
Upon starting river4.js I saw errors regarding modules that couldn't be found, starting with MD5. I didn't understand the error message and I was following Chris Dadswell's instructions put I couldn't put it together. As part of the process I created new AWS keys, which didn't solve the problem.
Finally, I read the error message more literally, googled "how to install md5 node module" and the first link was to this page with instructions to install the MD5 module. Subsequent attempts to run river4.js displayed errors for the missing modules opmlparser and feedparser, which then installed.
Upon getting all feedparser installed, I was able to get river4.js to start up successfully. I then decided to clean out all of the previous River4 data in my S3 and watched everything fill up as expected. My River4 page is slowly starting to fill up with new stories as they are found.
Having all the copies of my node.js apps on one server will make it easier to keep them up to date in the future.