Getting the message while running Testng - An exception stack trace is not available.

[Jay P]

Hi,

I am learning Selenium and have installed TestNG in Eclipse.
Was able to create some test classes and run yesterday, able to view test-output reports too. But today, the same classes are giving error and not running. The Error log shows: [TestNGLaunchConfigurationDelegate] Launching:  and I double click and see the message: An exception stack trace is not available.
Tried removing and re-installing testng, that also gives error:Cannot complete the install because one or more required items could not be found.
Not sure what changed since yesterday.

Can anyone please help me with the problem? Thank you.

Regards,
Jay