did the install go through completely? You might want to try a re-install, that helped in similar cases. If you have the PHP memory limit set to 8MB, try setting it to 10 or 12MB in php.ini
Are you speaking about the user Site of ez 3.0.2?
The Link, that gives the error, ends with /demo/content/view/full/211/ ?
I have the same problem here with a 3.0.2 site: There seems to be some demo data missing or has the wrong node-id. Don't care: if everything else works, you don't miss much.