I found the same issue using herd 4 and herd 5 Kubuntu alternative install CDs on my Compaq Evo N1020v. The Kubuntu graphical install cds have similar problems with partitioning on this machine. My somewhat long-winded workround was to install Edgy (in my case via the alternative install CD) then do a dist-upgrade to feisty.
I found the same issue using herd 4 and herd 5 Kubuntu alternative install CDs on my Compaq Evo N1020v. The Kubuntu graphical install cds have similar problems with partitioning on this machine. My somewhat long-winded workround was to install Edgy (in my case via the alternative install CD) then do a dist-upgrade to feisty.