when I try logging in it keeps on saying "minecraft quit unexpectedly"

Put the summary of the bug you're having here

What I expected to happen was...:
I thought it would log in with no problem

What actually happened was...:
It kept on saying that minecraft quit

---- YOU CAN CLOSE THIS LAUNCHER IF THE GAME STARTED OK ----
---- YOU CAN CLOSE THIS LAUNCHER IF THE GAME STARTED OK ----
---- YOU CAN CLOSE THIS LAUNCHER IF THE GAME STARTED OK ----
---- (We'll do this automatically later ;D) ----
Client> 2013-07-01 18:14:07 [CLIENT] [INFO] Setting user: nadeem_8
Client> 2013-07-01 18:14:07 [CLIENT] [INFO] (Session ID is token:58f0bdc53fb84b06b81af9efc7175d4a:c4df7d11fe06473591bd695576acceab)
Client> Invalid memory access of location 0x0 rip=0x0
Client> 
Game ended with bad state (exit code 139)
Deleting /Users/Nadoomi/Library/Application Support/minecraft/versions/1.6.1/1.6.1-natives-1372691646329075000

Steps to Reproduce:
1. open the launcher
2.Play

Also the annoying thing is that my computer cant be updated to 10.6 so i'm stuck on 10.5.8 meaning i can never play a newer version of minecraft again.