I now think there's an intermittent problem with the extras repository on repository.maemo.org, as I notice (in application manager) that several applications that used to be there are now apparently gone (e.g. 'zip', and also 'omweather' I think -- I have had it sitting in the 'upgrades' display for quite a while now without upgrading, and now it's gone).

That would explain why installing this had been working fine for some of us, but now it isn't working. I think the repo problem occured yesterday or today. Let's see what happens tomorrow or in the near future.