You DO know that this is a WINDOWS environment, right?
So there is no 'shell' as you would think of it in the *nix world. THUS shell commands don't work. (other than some that happen, by accident, to have the same name for the executable)
The Windows concept of a shell is the CMD command line interface, and all you can do there is manipulate things with Windows command line actions. In fact that is the way XAMPP works - everything is run through batch files that starts/stops processes/services. (ditto WAMP). All there is in the Windows world of executables is exe's (executables) and dll's (dynamic link libraries -- extensions for executables).
read this explanation about 'make/build' also:viewtopic.php?f=16&t=41029
Here's a good explanation of the realtionship between Windows and PHP extensions: (its even dead-on to your issue