Moreover why you don't send by yourself all these "small inputs" in one transaction and unlock this amount?
Add a decent size fee and you have your amount in 10-30 minutes.
obviously you don't have a transaction error

that's a really lame/silly excuse.
If someone can tell me how I can set up 500 transaction of 0.001 in one so I don't get the error, and I don't have to do it 500 times in transaction manually, I'd be happy not to ask for anything

what wallet are you using? if you load your private key in electrum it will be managed automatically.