Root lg eve root help

[basziee]

hi all
first of all sorry for my bad english i'm dutch
my question is how to root the eve

i see in the last pic:
236 KB/s <0 bytes in 18880.000s>
pkg: /data/local/tmp/Superuser.apk
Failure [INSTALL_FAILED_ALREADY_EXISTS]
why is my phone not rooted yet? if the Superuser file is installed?
i wanna root my phone because i wanna use metamorph
thanks for all the help

edit: i think this is the problem:
Type "adb shell chmod 4755 /system/bin/su" ( it give me an error )