The installation problem has now been solved.

Anonymous Monk on Feb 03, 2011 at 21:40 UTC put me on the right track. Before I posted my question, I had already checked if gcc was in my path by typing just gcc with no arguments. cmd.exe didn't complain about unknown command, instead gcc complained about not getting an input file, so I knew gcc was in my path. After posting my question and reading all answers, I followed the tip from the anonymous monk to type gcc -v instead, and that revealed something! It didn't say anything about MingW gcc (MingW is installed with the Strawberry Perl package), instead it said DJGPP gcc! Then I remembered that I installed DJGPP gcc port (http://www.delorie.com/djgpp/) a long time ago. When I checked the path variable, I saw that the directory with DJGPP's gcc.exe came before the directory of MingW's gcc.exe. I put DJGPP's directories last in the path variable, and then installing the CPAN packages worked. It was the wrong gcc used. Arghhh...!

The CPAN Client still doesn't work, but I don't care now that manual downloading and installing works.

Anonymous Monk on Feb 03, 2011 at 21:26 UTC suggested cpanp. I had never heard of cpanp before. Now I have, and might try it some time. Thanks!

BrowserUk, before there was tight limitation for the command line in Windows. I didn't know they had improved that in Vista. Now I know. Thanks!

Anonymous Monk on Feb 03, 2011 at 21:40 UTC; I meant the character limitation in cmd.exe . I never thought of that there might be a limitation in dmake as well. Thanks!

Anonymous Monk on Feb 03, 2011 at 22:00 UTC; your script only returned FTP_PASSIVE = 0. Thanks!

syphilis, thanks!

bart, I wrote that I had already tried turning the firewall off. But I wrote a lot, so it might have been easy to miss. Thanks!

All of this started when I wanted to make a small utility that uses the clipboard. My first thought was to do it in Qt C++, but I realized that colleages would complain and say "Why didn't you do it in Perl, it's much quicker to do things in Perl". So I better do it quickly in Perl, but after spending a whole day struggling with the CPAN Clipboard module I was about to give up and do it in Qt C++ anyway. It was just a last desperate thing to post a question here, but I didn'r really expect any answers. But the next morning there was five answers, and then more showed up! That gave me new energy to try more. Perlmonks is really a great place! Thanks a lot!