Hmmm. Can't help you directly. I've never done it with a crossover cable, although in theory it should work.
I do it all the time with a router - the machines connect via that, and there's a network for them to talk to. Very easy, and very effective.
Routers are very cheap (I think I paid about a fiver on Ebay for one). The two computers can also share the internet using one.
Just a thought: have you set the files/folders you want to access over the network as "shared"?