That was so simple Birdy - I turned the Firewall off, and redownloaded, and I'm in business. Didn't need Stuffit, though I expect it'll come in handy ...

I would be reluctant to remove any protection software - since joining Limewire I have been a little concerned at unwanted windows opening - or is this more with the free version, and not LWPro? (I'm not talking about LimeWire's own popups)