Install and upgrade woes

I am trying to upgrade my present v9 with 9.1.. All seems ok until I get to the choice of programs page and then it tells me it cannot find the media...There seems to be no way past this... I then tried a new install on a spare partition I went through the disk preparations and set the boot and format but once again it tells me it cannot find the media...Any advice appreciated.. -- Regards Ted Wager Using Debian Linux