Wierd Nuez crash

Howdy!

My client crashes after about 5 seconds in the world. I think my nuez is the problem but I'm not sure. This happens on most computers, But for other people it works with No problems I have all my ip's correct I'm at a total loss I'm not sure what to do. First i thought it was computer specs but, Their all win 7 computers, it works on my 8gb asus, and it works on my 4gb laptop then fails on my 12gb and fails on my 3 gb. I'm so confused. Anyone have any idea? or can point me in the right direction, Thanks a lot i really appreciate it.