Smart Contract Error – Encountering Error During Contract Execution [Reverted]

I see two issues, and I think the second is the source of your error:

function createTokens() payable{
    require(msg.value > 0);
    require(_totalSupply.add(tokens) <= maxTokens);
    uint256 tokens = msg.value.mul(RATE);
    balances[msg.sender] = balances[msg.sender].add(tokens);
    _totalSupply = _totalSupply.add(tokens);
    owner.transfer(msg.value);
    require(_totalSupply.add(tokens) <= maxTokens);
}

The line require(_totalSupply.add(tokens) <= maxTokens); occurs twice. Each time is problematic:

1. The first time, tokens has not yet been assigned a value. (I was surprised this even compiled, but apparently variable declarations are hoisted?) So this checks adding 0, which doesn't do what you want.
2. The second time, you've already added tokens to _totalSupply so you're effectively checking "Can I add tokens twice and still stay under maxTokens?"

I would fix the function by moving the earlier require to after the computation of tokens and getting rid of the require at the end:

function createTokens() payable{
    require(msg.value > 0);
    uint256 tokens = msg.value.mul(RATE);
    require(_totalSupply.add(tokens) <= maxTokens);
    balances[msg.sender] = balances[msg.sender].add(tokens);
    _totalSupply = _totalSupply.add(tokens);
    owner.transfer(msg.value);
}

In both transactions, your input data is empty and you are sending an amount of Ether to the contract. Because you are not calling a specific function, you will be calling the "fallback function" in the contract. That function is defined as:

// ---------
// Dont accept ETH;
// ---------
function () public payable { 
    revert();
}

Note that the function specifically denies a user sending Ether to the contract, causing the problem you are seeing. Thus, the error is by design, not a problem with the code.