Eclipse - Not able to run TestNG tests

I am using Eclipse Kepler 4.3.2 and have installed TestNG plug-in for it but am not able to run TestNG program as TestNG console is displaying below error.

"Plug-in org.testng.eclipse was unable to load class org.testng.eclipse.ui.TestRunnerViewPart."

I am not able to resolve this even after reinstalling the Eclipse and creating projects in new workspace.