missing POP3 mail

[Andrew Hilborne <andrew.hilborne@gxn.net>]

I'm running stock pgnus-0.97. Yesterday I lost some POP3 mail, and had to run
nnml-generate-nov-databases-1 in order to recover some other messages which
hadn't appeared in the appropriate groups.

These are my mail sources:

    (setq gnus-secondary-select-methods
            '((nnml "private" (nnmail-cache-accepted-message-ids t))
              (nndraft "private")))
    (setq mail-sources
          '((file :path "/var/mail/me")
            (pop :server "pop.isp.net"
                 :user "myid"
                 :password "somepass")))

The POP3 box is served by qpopper version 2.52. Sometimes, when the POP3 box is 
locked, qpopper will respond with a message (don't know number which and can't
replicate from here) saying to try again later.

Yesterday during the normal POP3 collection run this message was reproduced by
the fetchmail process in the minibuffer, and I was asked if I wished to
continue or not (yes/no.) I don't know what I typed, but I then lost POP3 mail, 
and some other mail which had not come through POP3 wasn't registered properly
in the appropriate NOV database. I use fancy-split. The missing POP3 mail
wasn't in the Incoming.* files. In fact I have lost it permanently :-(

Is this expected behaviour? Is this my fault for using beta software? What can
I do to prevent it happening again? All advice is appreciated...

Secondary question: how can I attach my POP3 server to a single group/set of
groups and only check it sometimes?

TIA.

--
Andrew Hilborne