ubuntu 8.04.1 installer

[Sérgio Neves]

Hi,
On my laptop, both the option to install and the option to start the desktop 
work well (orca speaks).
However, on my desktop, when I boot from the ubuntu 8.04.1 cd, press enter 
to select the english
language, press down arrow to install option, f5, three down arrows to 
screen
reader and two enters, the installer starts but orca doesn't speak. I did it 
with a sighted person, so I know I did it well. However, if I select the 
other option (to start the desktop), and after call orca, it speaks 
perfectly.
What could be the problem? Or what can I do to help diagnosing the problem?

Thanks

Best regards

Sérgio Neves