I've only made a cursory examination of the code, since I was simply
wondering how you handled error conditions within AnyEvent.
However, AnyEvent::RPC appears to call rpcfault, without defining it.
http://search.cpan.org/grep?cpanid=MONS&release=AnyEvent-RPC-0.05&string=rpcfault&i=1&F=1&n=1&C=0
Cheers,
N