Hi @Hendobox,
Welcome to the community 
I am sorry that you are having issues flattening. I assume that you are trying to verify your token contract on Etherscan.
I recommend using Buidler Etherscan plugin to verify as a multifile contract: https://github.com/nomiclabs/buidler/tree/master/packages/buidler-etherscan
If you run into any issues you can post your contract, address and license being used in the forum and I can have a look.
I also suggest having a look at using Windows Subsystem for Linux (WSL) for developing smart contracts on Windows: Solidity Smart Contract development on Windows