in... serv_calendar.c ical_send_out_invitations()
msg = CtdlMakeMessage(&CC->user, "", /* No single recipient here */ "", /* No single recipient here */ CC->room.QRname, 0, FMT_RFC822, "", "", summary_string, /* Use summary for subject */ NULL, request_message_text, NULL); these strings aren't const so "" is illegal. IG, you should fix that.
