is a faucet/investment site like btcflow? Because i see payment for upgrade

Your calculations are not right. Every User get for sign up 1000 Kisses start bonus. 1000 Kisses have the worth of 100 Satoshi.
With the 100 Satoshi you can upgrade the Book level by one.
If you calculate the hourly payout with payout per minute you will get estimated 2700 Kisses. That is 270 Satoshi an hour.

I tried to make a withdrawal today for 38,500 satoshi, which is well above your minimum balance. I got the error message "Not enough bitcoin in wallet". That's the amount I have in my balance, but I thought maybe the 400 satoshi transaction fee wasn't deducted from the withdrawal amount, as the notice claims. So I tried to cash out for 38,100. I got the same error message. So then I tried to cash out for 6,000 satoshi, which is the minimum. And I got the error message again.

Do you plan on paying your users, at all? Why would you launch a faucet that you haven't checked the withdrawal feature on? Unless the "not enough bitcoin in wallet" is talking about YOUR wallet.

What's going on, OP?