You can not install Win32 modules in x64 bit perl.
I beg to differ on that. It's been a while, but I seem to recall being able to install Win32 modules in 64-bit Perl before without any issues.
Ok, so maybe you don't want to take my word for it. Here's some links to release notes of 64-bit Strawberry Perl that includes various Win32 modules in the list of included modules.
If I remember correctly, ActiveState's releases of 64-bit version of their ActivePerl do not include Win32 modules. However, that does not mean that Win32 modules cannot be installed in 64-bit Perl.