I have a problom with dowload the mcaselector

so, i tried dowloading a world to my server and i got a problom that its on bedrock. some1 got me to a website that changes the version.(chunker) then i says me: the file is too big. then i went to a website called: GitHub (withc can reset ur chunks and minimize ur wolrd file) and then i tried to dowload the thing and when i tried to open it: it got me a error. in the error writen: “Error: A JNI error has accurred, please check youre installetion and try again.” and then when i press “ok” another error that writen: “A Java Exception has accurred.” how do i fix that? i really need it