For me, It doesn't happen all of the time. If you jump from one menu to another (main menu) it should happen a little too often. There's a reference to a "PEAR" directory in libraries, when I enable joomla's debugging, but I couldn't find the file it referred to in the libraries folder.
I really like enonews' simplicity, but something's wrong there. The error is occurring, even on a different server.