Problem incorporating old mail from Thunderbird

[Angel de Vicente]

Hi,

I'm trying to import all my archived mail, which until now I was
managing with Thunderbird. I have several archive files in Thunderbird,
and all of them have worked very well when importing to Gnus (G f), but
with one of them, it only finds 3 articles, despite the actual number
being around 3700. 

The *Messages* buffer doesn't show any possible errors.

============
Retrieving newsgroup: nndoc+/home/angelv/2009:2009...
Opening nndoc server on /home/angelv/2009...done
Fetching headers for nndoc+/home/angelv/2009:2009...done
Generating summary...done
No old news.
============

Any idea what could be the problem and how to solve it?

Thanks,
-- 
Ángel de Vicente
http://angel-de-vicente.blogspot.com/