Urgent reply needed for error message Index (zero based) must be greater than or equal to zero and less than the size of the argument list

I am using register user control with some custom controls added to it. When I press create user button it gives error
Index (zero based) must be greater than or equal to zero and less than the size of the argument list Following is the stack trace
[FormatException: Index (zero based) must be greater than or equal to zero and less than the size of the argument list.] System.Text.StringBuilder.AppendFormat(IFormatProvider provider, String format, Object[] args) +11118244 System.String.Format(IFormatProvider provider, String format, Object[] args) +63 System.Web.UI.WebControls.CreateUserWizard.AttemptCreateUser() +971 System.Web.UI.WebControls.CreateUserWizard.OnNextButtonClick(WizardNavigationEventArgs e) +110 System.Web.UI.WebControls.Wizard.OnBubbleEvent(Object source, EventArgs e) +401 System.Web.UI.WebControls.CreateUserWizard.OnBubbleEvent(Object source, EventArgs e) +119 System.Web.U ...