Simple reason is you cant' as Oracle does no allow third parties to redistribute their binaries. So Activestate will not serve them up anymore.
Have a look at the README.win32.txt found with the distribution. It has a good section on how to install DBD Oracle from scratch, There is a allot of downloading but it is relatively straightforward.
by the way you would be much better of using perl.dbi.users list as nobody reads this one except for me