I know this is an old question, but it took me several hours to find the answer, and that only by reading German
. Maybe someone can benefit from what I found.
Cyradm requires the file IMAP.so in /usr/lib/perl5/5.8.8/Cyrus (or whatever your Perl library path is), in addition to IMAP.pm, IMAP/Admin.pm, IMAP/Shell.pm, and IMAP/IMSP.pm. I found IMAP.so in ./perl/imap/blib/arch/auto/Cyrus/IMAP/IMAP.so in the source directory. I'm still having trouble authenticating to the server, but at least I can get into cyradm now.