MDT 2012 Unable to edit unattend.xml file

Hi All,

I have created a new WIM and imported to my operating systems. I created a task sequence successfully and now when I try to edit unattend.xml file i get the following error 

" Microsoft.BDD.Catalog40". Below is the log 

Problem signature:

  Problem Event Name:CLR20r3

  Problem Signature 01:microsoft.bdd.catalog40.exe

  Problem Signature 02:6.2.5019.0

  Problem Signature 03:520e8f2f

  Problem Signature 04:Microsoft.ComponentStudio.ComponentPlatformInterface

  Problem Signature 05:6.3.9600.16384

  Problem Signature 06:5215ca3e

  Problem Signature 07:438

  Problem Signature 08:2a

  Problem Signature 09:System.IO.InvalidDataException

  OS Version:6.1.7601.2.1.0.400.8

  Locale ID:1033

  Additional Information 1:f75e

  Additional Information 2:f75e2cd954580e4c521ce4d8f8ca3324

  Additional Information 3:f2f4

  Additional Information 4:f2f402fdc8e9c74856ae83c38f1e3e25

All other task sequences are working fine. Can someone please assist.  Thanks