DISM /Set-TargetPath failed, rc = 5.

Hi need some help

i have just created a deployment share using MDT 2012 update 1. When i come to update the deployment share to build the the boot media i get the following error.

Exit code = 5

DISM /Set-TargetPath failed, rc = 5.

DISM was unable to set the system root (target path) for the Windows PE image, so the update process cannot continue

I have removed my anti virus and fire wall i have tried to update the deployment share on c: incase its an access premission. i have got windows 7 sp1 i had to down load the automated installation kit as mst just keeps giving an error on msxml 6.0. any ideas ?

Regards

Carl