As Corion said above, you need to read the errors and let that help determine what the issue may be. It could be a permission thing (yes, even on Windows). I have a Win7 machine that works just fine - I'm an admin. But my work Win7 machine (where I'm not admin) will not let me install modules from CPAN - all failing with "... permission ..." errors - usually about CPAN client not being able to write a lockfile.

I've created a custom MyConfig.pm and use PREFIX=%USERPROFILE%/perl for installs and that seems to work most times.