Hmm, I'm set up on 128 bit WEP. Any reason it shouldn't work?
I suppose I could change to WAP, but it would mean resetting everything on the net, including the HP 3310, and I'll have to check and see if it supports it. I'd rather not.
(Also found thA, after opening and shutting the network assistant once, it will not open again. So much for infallible Mac software...)