I'm going to assume that you have 32-bit ActivePerl. (For 64-bit Perl, I think you need to get Visual Studio or some free download related to it to get the files you need. It's been a while since I looked into that, so things might have changed.)
To install Win32::GuiTest, you might need check other repositories or you might need to go directly to CPAN. Unfortunately, ActivePerl does not have a compiler or make utility installed by default. Here's what you should try.
- Install MinGW and dmake from ActiveState's repository using PPM.
- Now just open a command prompt to install from CPAN by typing: cpan install Win32::GuiTest
- The first time running cpan, you'll probably be asked for some information to configure the cpan module.
- If you're behind a web proxy server, you'll need to either configure the cpan module with the information or add environment variables to the OS, such as http_proxy.
- You might also need to open the command prompt with "Run As administrator".
If I remember correctly, Win32::GuiTest should install from CPAN without issues in 32-bit ActivePerl.