I think the subject covers it. Here's the error:

Making install in convert make[3]: Entering directory /root/dovecot-1.0.beta3/src/plugins/convert' make[4]: Entering directory /root/dovecot-1.0.beta3/src/plugins/convert' mkdir -p -- /usr/lib/dovecot/imap /usr/lib/dovecot/pop3 /usr/lib/dovecot/lda for d in imap pop3 lda; do
rm -f /usr/lib/dovecot/$d/lib02_trash_plugin.so;
ln -s ../lib01_convert_plugin.so /usr/lib/dovecot/$d;
done ln: /usr/lib/dovecot/imap/lib01_convert_plugin.so': File exists ln: /usr/lib/dovecot/pop3/lib01_convert_plugin.so': File exists ln: `/usr/lib/dovecot/lda/lib01_convert_plugin.so': File exists

Richard