I'm trying to have my Minecraft appdata folder on a different partition (from now on referred to as `D:`). This is what should be where:  

    D:
        Steam
        Minecraft
            .minecraft

This is my batch file:

    @ECHO OFF
    SET APPDATA= D:\Minecraft
    CD /D %~dp0
    java -jar minecraft.jar

It's supposed to set the `%APPDATA%` folder (where Minecraft stores its data) to `D:\Minecraft`, go there, and launch the `minecraft.jar` downloaded from [minecraft.net][1]. However, when I run it, I get the following error:

    Exception in thread "main" net.minecraft.bootstrap.FatalBootstrapError: Unable to create directory:  D:\Minecraft\.minecraft  
            at net.minecraft.bootstrap.Bootstrap.main(Bootstrap.java:369)

What am I doing wrong? Have the steps for making Minecraft portable in 1.6.2 differed?

  [1]: http://minecraft.net