Hmm... Let's see if I can help you, so let's start with:
What OS are you using? Did you download the full version or just the update?
And are you using any mods or game decompilers?
Cheers!
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