> We can definitely improve upon how the error gets reported.

Certainly. Patches welcome. :-)

>     Error contacting: http://blah.blah.blah:/archive-contents
>     error in process filter: peculiar error: 404 [2 times]
>
> To the user, the first error gives sufficient hint for futher action.
> I wonder what the second error says which the first error already
> doesn't say.

The second error is saying that the page was not found. I imagine other
things that can happen are request time-out and certificate issues.

The 404 error is so well known that I'm not too worried about confusing the
user. I'd rather not hide this possibility-useful information in fear that
someone might be freaked out by it.

But improving its presentation is certainly possible.