using swish-e to search gnus mail archives

[Angelina Carlton <brat@magma.ca>]

Hello everyone,
I have followed the directions here:
http://my.gnus.org/node/217
to set up swish-e as a way to index and search my mail archives.
The swish-e application, from the command line works perfectly:

,----
| [orchid@lemonjelly:~] $ swish-e -f ~/Mail/index.swish-e -w "Gift
| Certificate"
| # SWISH format: 2.4.3
| # Search words: Gift Certificate
| # Removed stopwords:
| # Number of hits: 7
| # Search time: 0.546 seconds
| # Run time: 0.573 seconds
| 1000 /home/orchid/Mail/inbox/5141 "Gift Certificate" 18391
| 565 /home/orchid/Mail/inbox/3911 "3911" 802738
| 565 /home/orchid/Mail/inbox/2859 "2859" 802738
| 257 /home/orchid/Mail/grrls-only/812 "812" 7799
| 257 /home/orchid/Mail/grrls-only/2565 "2565" 5962
| 199 /home/orchid/Mail/grrls-only/44 "44" 5397
| 199 /home/orchid/Mail/debian-user/8312 "8312" 4001
`----

So now all I needed to do was to get gnus to generate a swish-e buffer,
following the instructions on the site, I included this in my .gnus-el:

,----
| ;; swish-e --------------------------------------------------------------
| ;; apt-get install swish-e
| ;; whet wget ftp://ftp.is.informatik.uni-duisburg.de/pub/src/emacs/nnir.el
| (require 'nnir)
| (setq nnir-mail-backend (nth 0 gnus-secondary-select-methods)
|       nnir-search-engine 'swish-e)
`----

Now from the the summary buffer I press G G and I am asked for a query,
after that I get a beep and in the minibuffer:

Wrong type argument: arrayp, nil

I do get the buffer  *Summary nnir:((query . "Gift Certificate"))* but
alas it is empty.... 

the *Messages* buffer contains:

,----
| Opening nnir server on -ephemeral...done
| Doing swish-e query ((query . Gift Certificate))...
| swish-e args: -f /home/orchid/Mail/index.swish-e -w Gift Certificate
| Loading cl-seq...done
| Massaging swish-e output...done
| Doing swish-e query ((query . Gift Certificate))...
| swish-e args: -f /home/orchid/Mail/index.swish-e -w Gift Certificate
| Massaging swish-e output...done
| Doing swish-e query ((query . Gift Certificate))...
| swish-e args: -f /home/orchid/Mail/index.swish-e -w Gift Certificate
| Massaging swish-e output...done
| Retrieving newsgroup: nnir:((query . "Gift Certificate"))...
| Fetching headers for nnir:((query . "Gift Certificate"))...
| mail-header-set-number: Wrong type argument: arrayp, nil
`----

I don't know what this last function does even with the built-in help it
is unclear to me what I need to do.
,----
| mail-header-set-number is a Lisp macro in `nnheader'.
| (mail-header-set-number HEADER NUMBER)
| 
| Set article number of HEADER to NUMBER.
`----


Please if someone could tell me how to get this working I would be so
happy, I really like the idea of a search buffer inside gnus instead of
command line tools like grepmail or just plain old grep!

Thanks in advance 
-- 
-----Angelina Carlton-----
orchid on irc.freenode.net
     brat@magma.ca
web:bzgirl.bakadigital.com
--------------------------