We are not sure what causes this, but would like to learn more. If you run into this situation, please let us know. We want to track this down. In the mean time, you can usually remedy the situation by just opening Safari and browsing to a website then returning to Next Read.
Edit: Looks like this situation is not unique to us. There is an Apple Support Discussion Thread about this very topic.
While we are on the topic. This is one of the many issues with the iTunes app store. People are using the review system as a sounding board when they run into issues. Sure, Apple provides a handy little link back to the developers website, but how many people actually click on that link? It doesn't do anyone any good to have crash reports muddying up an app's reviews. There are plenty of cases of that throughout the store. What ends up happening is that the review system loses credit and people start ignoring it. And don't even get me started on the "review on delete" 2.2 feature.
So how to fix it? One way would be to provide the user a way to "Submit an Issue" right from the store. Or how about just letting developers contact the people that write reviews? What if someone writes a really great review and we just want to get in touch with them to provide some free stuff? Or how about simply letting developers respond to reviews? How many apps have you seen on the store where the developer has to add, in the description of their app, "If you are encountering this crash..."? Thats just wrong. That information does not belong in the app description. Unfortunately, the developer has no place else to put it where it will get noticed.
The current system is broken. So, that leaves us in a situation where we have to post a blog entry and hope that people running into this issue take the time to visit our website. So, if thats you, cheers. Thanks for taking the time.