By default ActiveState doesn't come with a C compiler, or build tools. Many CPAN modules contain no C code, pure perl so you may never had needed this so far. If you're going to be using Perl on windows you can make your life a lot easier by switching to Strawbery Perl, since it ships with a sane development environment, lots of additional modules and libraries as standard. libssh2 install doc. You can see how builds/packages everything.