So after a reinstall of OpenSolaris and starting from scratch and carefully going through the newly learned steps of setting up my home file server, I finally got it working to the stage when the server had a ZFS pool and could share it over the network and I could read and write to it. I recorded the terminal commands that I used to get it going in a Google Doc if anyone wants to try if for themselves.
However, every time I tried to copy anything big to it, it would disappear off the network until it was rebooted. Not sure what is causing this and the OpenSolaris community aren't newbie friendly. In fact, they're not helpful at all. The problem could be a hardware fault, but I don't know my way around OpenSolaris well enough to determine that and operating systems that require terminal commands to get anything done just seems so... '80's...
I'm not giving up just yet though. Today, Uncle Phil is donating his old PC to the cause. It's a PC that he doesn't use anymore because he now has an iMac, something that's been happening a bit in our circle of friends lately. Phil's old PC isn't shabby at all, with a Core2Duo processor and plenty of RAM so it'll be interesting if this makes a difference.
Here we go again!