the CPAN utility will use the ftp command-line utility to do FTP's. If it cannot find 'ftp', it cannot get the information from your mirror. It might be a search path problem for the user account or the utility got moved or deleted.
Please correct me if I am getting you wrong, is CPAN using FTP protocol to connect to the local mirror?
Comment on Re^4: Installing Perl modules automatically
If you have a local mirror of CPAN and can access all files with ``file:'' URLs, then you only need a perl better than perl5.003 to run this module. Otherwise Net::FTP is strongly recommended. LWP may be required for non-UNIX systems or if your nearest CPAN site is associated with a URL that is not ftp:.
If you have neither Net::FTP nor LWP, there is a fallback mechanism implemented for an external ftp command or for an external lynx command.