I'm new to unity3d. I installed the free windows version on vista (400 MB download, approximately) and after that I looked for hte islandemo but it wasnt there. So I downloaded the Island and installed it but when i tried to open it, it said the project had to be converted to the newer version. SO I let it do the conversion, but now when i try to run it,it says all compiler errors have to be fixed to runit. :/
I also tried installing the shadowdemoproject. When I run it I just see a blue screen :/
When it says you have to fix all the compiler errors, that means exactly that: fix all compiler errors. The island demo was written for an earlier version of Unity, and some stuff changed in Unity 3, so it's not compatible anymore. If you don't know how to fix the errors, you probably shouldn't bother with it for now.
Xsistor... To fix the errors, click on the bottom left, should be red, and it'll open the log... I'd just comment everything that says it doesn't work right... Keep in mind, this'll make other parts of the script non-working, so it could take some time, AND to further that, it'll stop some of the things the demo has to offer... But their are other demos you can look out, I'd suggest checking those out =).