If you add a trailing / to the install path when doing a ftp install the installation program adds a / of its own. This means if you specify to retrieve from ftp.goatcheese.org and download from /home/miah/alpha/ the installation program will try to download from /home/miah/alpha//RedHat/base.
That is a perfectly valid UNIX path.
i had the same problem but go the ftp install to work... if i was installing using the ncsu.edu servers i would have typed the following: ftp.linux.ncsu.edu pub/fedora/linux/core/2/i386/os using that did not cause and extra slash to be inserted into the full address