If you are a windows user, please check the link for the reason.
It may you due to your system configuration. Check whether your computer has the system requirement required for installing moodle.
This error message mainly occurs when your System's window is 32 bit and you are trying to run 64-bit XAMPP program on the 32-bit operating system.
Try to install a version of XAMPP compatible to your window.
Please check your system configuration before installing XAMPP and Moodle