If you are facing issues, tell me: What is your Operating System (Windows 10/11)? What is the exact error message you see? Did you try running it as an administrator ?

Offers a version for Windows with an integrated downloader and installer. Horizon Aarc (Developer Site):

Kundli Pro 5.5 is a popular Vedic astrology software used for creating birth charts (Kundli), matching horoscopes for marriage (Kundli Milan), and generating various astrological reports. Below is the proper procedure for obtaining, updating, and installing the software.