STS Installation end up with unable to load class error


I am following this link and installed STS. When open STS application, it shows the below error, Am I Missing something?

Plug-in org.springsource.ide.eclipse.commons.gettingstarted was unable to load class org.springsource.ide.eclipse.commons.gettingstarted.dashboard.WelcomeDashboard.
  1. Using Windows 7 Enterprise
  2. Downloaded Java 1.8 and setup JAVA_HOME env variable
  3. Downloaded STS 3.8.3 Release for Windows from “http:9+//”

A day before I’ve installed Eclipse Neon and tested “Helo world” simple program, it was working fine…I am not familiar how to plugin Maven, so completly removed Eclipse from laptop and trying to install STS and endup with this error…

any help?