Hey Ann, try this.
Inside your express share, check the sysprep folder and edit the sysprep file, i.e standardxp.inf and comment out (i.e use a semicolon in front of the line) so that the following synatax looks like this.
[Unattended]
OemSkipEula=Yes
; InstallFilesPath=%BOOTDRIVE%Sysprep\i386
UnattendMode=FullUnattended
DriverSigningPolicy=Ignore
OemPnPDriversPath=drivers
UpdateInstalledDrivers=Yes
EMSSkipUnattendProcessing=Yes