Hi Shekkar_Pandy,
Thank you very much for your advice.
However I had discovered that in my case the reason for error was that I installed Java and set up JAVA-HOME after installing elasticsearch, logstash and kibana. The result was that not all of the folders unpacked from the zip folder. So I deleted logstash folder and extracted them again to elk folder on C:\ drive. This time all folders extracted and installed correctly, including vendor folder with Jruby in it.
