imap subscribing to new group creates bogus server, broken group

[Chris Shenton <chris@shenton.org>]

Running No Gnus v0.3 on FreeBSD-4.10 against courier-imap over ssl.

I see this problem frequently and haven't come up with a fix or
reliable workaround. I have an nnimap server named "NewHorse".  A
split looks for lists and puts them into groups based on the list
name.  When I subscribe to a new list, the mail comes in and gnus
appears to do the split. 

First problem is that gnus doesn't ever show me this group in my
*Group* buffer. I go into the server buffer, find the new group marked
with a "K", do a "U" on it.  Back in *Group* I try to enter the group,
it says "Couldn't open server".  Back ni *Server* it shows an
obviously broken group; here's my list:

     {nnml:archive} (opened)
     {nnimap:NewHorse+nnimap+NewHorse:INBOX.list.zope} (denied)
     {nnimap:NewHorse} (opened)
     {nnml:} (opened)


Looks like there's some mis-parsing or mis-appending going on.  The
new group should be "INBOX.list.zope" in server {nnimap:NewHorse}.  I
can't even "k" kill-server, the error says it's "Read-only server
$uglyname".

How do I un-mangle corrupted server/group things?

How do I prevent the corruption from occurring in the first place?

How do I get newly-appeared groups on the server to appear subscribed
in *Groups*?

Below, I've excerpted what I hope will be the relevant parts of my
.gnus file.  

Thanks.

(setq gnus-select-method '(nnnil))	;HQ has no news server

(setq
 gnus-secondary-select-methods
 '(
   (nnml "")				;pop, files
   (nnimap "NewHorse"
	   (nnimap-address "newhorse")
	   (nnimap-stream ssl))
))

(setq					; Splitting
 nnimap-split-crosspost	nil		; unduped freebsd articles? first match
 nnimap-split-inbox	'("INBOX")
 nnimap-split-predicate "UNDELETED"	; default = UNSEEN UNDELETED
 nnimap-split-fancy	nil
 nnimap-split-download-body nil		; default = 'default = nil for now
 nnimap-split-rule
 '(		;unmatched msgs stay in INBOX
   ;; determine list from list-managers headers
   ("INBOX.list.\\1"	"^List-Post: <mailto:\\([a-z-]+\\)@")   ; mailman
   ("INBOX.list.\\1"	"^Delivered-To: mailing list \\([a-z-]+\\)@") ;ezmlm
   ("INBOX.list.\\1"	"^Sender: owner-\\([a-z-]+\\)@")	;freebsd et al
   ("INBOX.list.\\1"	"^Sender: \\([a-z-]+\\)-owner@")	;gnus ding list
   ("INBOX.list.\\1"	"^List-Unsubscribe: <mailto:leave-\\([a-z-]+\\)-.*@")
   ;; turbine -- should have been matched by List-Post
   ))

(setq
 gnus-subscribe-newsgroup-method 'gnus-subscribe-hierarchically 
)