You can not run Vista Genome Browser because Java is disabled by your browser.
This can be changed in the browser settings.
To enable Java in your Mozilla or Netscape browser, go to the Edit menu, then go to Preferences. Click on "Advanced" in the left-hand menu, and check the box next to "Enable Java"
To enable Java in your Internet Explorer browser, go to the Tools menu, then go to Internet Options. Click on the "Advanced" tab and scroll down until you see an item called "Java (Sun)". Underneath it there will be a checkbox marked "Use Java 2 v1.4.2 for <applet> (requires restart)" (the exact version number may be different). Check that box, click OK, then restart your browser.