1John5vs7

I'm running Ubuntu 14.10 on my machine and having all sorts of a time trying to get ModLoader 1.8 to install. I have downloaded and updated Minecraft to version 1.8.1. Minecraft vanilla works just fine. Now according to the Ubuntu community, the easiest way to install mods for Minecraft on Ubuntu is with the ModLoader, but I can't get ModLoader to install! I've downloaded the .jar file, I made sure to enable permissions for the file to run, and when I run it in Java 8 Runtime, I get the little spiffy GUI that asks if I want to install client, server, or extract. The folder where it specifies my .minecraft folder is located is correct (home/[username]/.minecraft), but when I click the radio button next to "install client" and hit "ok", I get an immediate popup error stating "You must run the version 1.8 at least once." That is rather unhelpful as I've run Minecraft version 1.8.1 numerous times. Any thoughts on what I need to do to get around this problem? Do I need to maybe open my minecraft.jar file as an archive and move some of teh files from the modloader .jar into that archive? Thanks for your assistance!