can't Login

Put the summary of the bug you're having here

What I expected to happen was...:
I downloaded a texture pack and wantet to use it.

What actually happened was...:
I downloaded a texture pack and it kicked me from Minecraft. Now i think i need to put the tex. on off,but i CAN'T get into Minecraft...
Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...