I had to upgrade my autoconf and such a few times in order to get a few programs to compile, also. This is what I found out:
Mandrake stores most the files you need to replace in /usr/bin/<filename> which links to another file name with the version in it. In my case it would be:
/usr/bin/autoconf which links to /usr/bin/autoconf-2.13 (before the upgrade) .
I did not use mandrake RPMs to upgrade mine, I went to
http://www.gnu.org/directory/autoconf.html and downloaded and compiled the version I needed. This stored the new file in /usr/bin/local without the extension as part of the file name. I logged in as root, changed to /usr/bin, renamed the linking file autoconf to autoconf-bak, then moved /usr/bin/local/autoconf to the /usr/bin directory. If there are other files in the /usr/bin/local directory that were created during the autoconf compile, you will also need to move those to /usr/bin, take care to rename the files to something like *-bak just in case something goes wrong and you need to revert back.
I hope I have helped point you in the right direction.