Take into account that the "update only" file is for V0.48 to V0.49, using it on V0.46 will not work, you'll need to download the full V0.49 version in that case.
Now that's a first... Maybe a corrupted file 🤔
Here try with this link that is a packed version https://nopy.to/17R49K02/Ataegina-0.4.9-pc.zip
Let me know if it solves your problem