first of all, thanks to all of you for your quick replies.
the code I've provided is the only code in my script !!

and with those simple 4 lines, it doesn't work

I've tried to add a "sleep 5" before the key press: no success
I've tried the SetFocus command: no success.

and about the program I'm trying to install: Acrobat Reader, I think it's the same problem with all Installshield setups (Office 97 I think it's like that).

I'm going to test with the UDF script of Shell Command and I'll tell you if it works.

thanks