Put the summary of the bug you're having here

What I expected to happen was...:
I can play on single player or multi player

What actually happened was...:
when i go to play on either single player or multi player but the game chrashes as soon as i launch into either a server or a single player game

Steps to Reproduce:
1. upload any texture pack
2. go to play one either single player or multi player
3. it wont work any you get a crash report on what happened and you can never play unless you use default texture pack