It is indeed the IMAP server sending bogus IMAP:
(NIL NIL NIL "ubishops.ca")
is not a valid IMAP envelope, since the third element can only be NIL to
indicate the end of a group.
Nevertheless, c-client should not crash. It turns out that I've already fixed
it in imap-2002. Get the latest imap-2002 development snapshot:
ftp://ftp.cac.washington.edu/mail/imap-2002.DEV.tar.Z
That IMAP server also seems to be sending bogus text sizes, so you will
probably have other problems with it.
