i had the same problem, this is the way i solved it:
WIHU Install CFG:
___________________________________________________________
description.0=Microsoft Office
selected.0=0
collapsed.0 =0
command.0=cmd.exe /C @echo off
/user:DOMAIN\USER
help.0=%wihu%/office.rtf
Group.0=1
; Sub command 0.0
description.0.0=Office XP Standard
command.0.0=%systemdrive%\Install\CMD-Install\OfficeXP-STD.cmd
selected.0.0 =0
; Sub command 0.1
description.0.1=Office XP Full
command.0.1=%systemdrive%\Install\CMD-Install\OfficeXP-FULL.cmd
selected.0.1 =0
; Sub command 0.2
description.0.2=Office XP Standard + Access
command.0.2=%systemdrive%\Install\CMD-Install\OfficeXP-STD-AC.cmd
selected.0.2 =0
; Sub command 0.3
description.0.3=Office XP Standard + Frontpage
command.0.3=%systemdrive%\Install\CMD-Install\OfficeXP-STD-AC.cmd
selected.0.3 =0
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And in the commands file Wihu calls up contains:
-------------
cmdow @ /HID
@echo off
call %PATH-TO-OFFICE%\INSTAPLS.EXE TRANSFORMS=standard.MST /qr
exit
-------------
only different MST files for each command file tough..
I think the error occours because wihu has a log variable and office might have the same variable so they crash, if you run office instapls.exe without any switches you get the error message that it can not write to log file.
changing the LOG variable in WIHU might do the trick??