[Pan-users] Weirdness compounded : giganews on one machine but not another

[Beartooth]

I keep Pan 0.14.2.91 on four machines, with all the settings as near the
same as I can manage (except that three of them, being backups, aren't
subscribed to a lot of groups that are on the main one but that I seldom
look at). 

The main one (the same one that seemed to lose my lists of posts to bitrot
yesterday) connects as usual to news.opera.no, news.grc.com, and
news.gmane.org -- but not to news.isp.giganews.com. The backup does all
four.

I looked at Tools > News Servers > Giganews on both, and see no
differences; I even retyped my password on the main machine, in case that
had gotten corrupted somehow.

The little box lower left says Tasks 0/3 ; if I click on it, it shows the
little icon as connected, and whatever groups  I've tried to look at on
giganews as Queued; trying to restart it generally produces a message in
the log saying, for instance : 

Thu, 09 Mar 2006 10:15:36 - pan - queue_requeue_failed_tasks: assertion 
`queue_get_task_status(task) == QUEUE_TASK_STATUS_STOPPED' failed

What's wrong, and what do I do about it? 

Just on a hunch, what is Pan's cache, and what do I lose if I clear it?
(Oh, and how? I know there's a way ....)

-- 
Beartooth Staffwright, PhD Neo-Redneck Linux Convert
Pine 4.64, Pan 0.14.2.91; Privoxy 3.0.3;  Dillo 0.8.5
Galeon 2.0.0, Epiphany 1.6.5, Opera 8.52, Firefox 1.0.7
Remember I know precious little of what I am talking about.