re.: the fatal error; absolutely no idea I'm afraid, this is the first report of this occurring, even though the last release is 3 months out and has been downloaded approximately 40.000 times since then. no idea how to debug (yet) that I'm afraid ... :-(
re.: cache size, there's info in the FAQ describing why this happens and how to configure AO to not do that (hint: exclude page- or request-specific inline JS).
frank