when trying to install the pre release it says that the aux.class file doesnt exist so i cant move the new one to the .jar file.

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here It should let me play 1.5 on the pre release

What actually happened was...:
Describe what happened here i only got a black screen either after the mojang logo or after i login in

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...