I can explain that error.
The module PadWalker is a dependency of Spreadsheet::WriteExcel. PadWalker apparently uses some XS code, which requires a C compiler. Since ActiveState Perl was compiled with Microsoft Visual Studio it is looking for a program called "cl" which is a command line C compiler that comes with Visual Studio.
You may be able to get it working by downloading Visual C++ Express and adding its bin directory to your path. But If you aren't planning on doing any C development in the future, you are better off just installing the precompiled PPM as another commenter suggested, here are some instructions on how to do that.