I don't think Queasy Install is available at all right now. Today I did some troubleshooting for a customer who happened to be running Citadel. The trouble report was "mail is no longer forwarding" which to someone who knows the system a little better would actually translate to "my Sieve script is no longer running." Turned out the real problem was "citserver crashes when Sieve gets around to processing this one message in my inbox" and that's exactly what was happening -- every time a new message arrived in the inbox, Sieve would start up, but it would start with the first unhandled message -- which happened to be the corrupt one. And it would crash again. The customer didn't know that citserver was crashing because WebCit and IMAP clients happily reconnect to citserver, which of course restarts after a crash (rather quickly, in this case, because it's fast hardware).
I wonder how many of the people reporting Sieve trouble in the support forum are actually having this kind of problem, and simply don't know it? (Feel free to reply "duh, ig ... we already knew that" if this has already been discussed and I missed it.)