Upgrade XP asms error inquiry

Hi,

I am upgrading my XP Pro 2600 to the latest XP (with SP1 and 2) and all is
okay except near the finish I get this message and can't get past it.

Fatal Error

One of the components that Windows needs to continue setup could not be
installed. The paramete is incorrect.
The setuperr.log file says \i386\asms The paramater is incorrect.

I have googled a bit and found that it seems to be it doesn't recognise the
Cdrom.

The trouble is I don't know the best way to stop the setup so I can attempt
to change the Cdrom drives or do whatever I can.

Some have said one can copy the Controls.man file from the i\386 dir, but
I'm not sure about this.

Every time I okay that message panel, it goes to continue the setup which
takes me back to that panel again.

Any help here please?

Thanks

rock