Password matching regular expression does not work in IE 6 & 7

I'm using the Asp.net change password control in my application and all seems to be find But there is a error occurs when validating the password.(Validation fails only in IE 6 & 7)

Here is the regex I'm using:

^(?!\d)(?!.*(.)\1)(?=.*\d)[\w\d$@#]{8,10}$

The Password does not validate according to the regex.Even though we entered the correct password it gives it as invalid password