RemminyCricket

Hello, I am new and could not find my answer in the tutorials or search engine for the forum. I downloaded the latest version of eclipse and the library files. When I installed the library files I clicked run one, two and three. I got errors with three. Also i'm a bit paranoid about my computer, I would like to know that the program is all safe to use and that it is free. Also is that how I correctly install the library files? If so why did some of them not install on the run three. Thanks for your help!