Error 1706. No valid source....for MS Office 2000

I have installed MS Office 2000 onto my new Vista Business PC. I went to add
the additional feature (Programs Features,MS Office,Change,Add Features,etc,
etc) and when asked to locate the DATA1.MSI file, I put the CD in the
Drive................but I was then presented with 'Error 1706. No valid
source could be found for product Microsoft Office 2000'. I have an external
drive on this PC, so I tried the CD in there............still no luck.

I placed the CD on a shared drive on a Windows 2000 Server PC and it worked!

Is this Vista being over protective and not allowing me to gain access to
either (a) my own DVD drive!!, or (b) the DATA1.MSI file?

I would love to know!!

Thanks all.