Instead it is caused by a Twitpocalypse, a Twitpocalypse is is similar to the Y2K bug. The unique identifier associated to each tweet has now exceeded 2,147,483,647
For some of your favorite third-party Twitter services not designed to handle such a case, the sequence will suddenly turn into negative numbers. At this point, they are very likely to malfunction or crash.
Copied from http://www.twitpocalypse.com/
Now waiting for this app to appear as a update in the apple app store, though this sounds like it may be a while before it comes out.