JMeter Installation

How can I solve this error when running JMeter:

Jmeter alternative

I'm looking for a freeware / simpler alternative to JMeter. It is a very complete yet complex tool and all I need is to simulate a number of simultaneous calls to a site, grab stats about performance (time to the response) and see how many concurrent calls it can endure without breaking. Some chart thrown in would be useful.

JMeter Tutorial for Beginners

Learn Jmeter from scratch.