Separate contract calling mint from token contract

Question

I have a standard ERC20 token contract with minting functions:

pragma solidity ^0.4.11;

import "./Stake.sol";
import "./Mint.sol";

contract Token is Stake, Mint {
    //omitted standard ERC20 text
}

The minting contract that this inherits from is the following:

pragma solidity ^0.4.11;

import "./BaseToken.sol";

contract Mint is BaseToken {

  // Mint state
  address public centralMinter;
  uint256 public totalMinted;

  // modifer
  modifier onlyMinter {
    if (msg.sender != centralMinter) revert();
    _;
  }
  function Mint() {
    // constructor
  }

  function mint(address _to, uint256 _amountToMint) onlyMinter() {
    balances[_to] += _amountToMint;
    totalSupply += _amountToMint;
    Transfer(this, _to, _amountToMint);
  }
}

Now, I have a Relay contract that inherits Token:

pragma solidity ^0.4.11;

import "./Token.sol";

contract Relay is Token {

  uint256 public approvalCount;
  function Relay() {
    // constructor
  }


  modifier onlyOwner {
    if (msg.sender != owner) revert();
    _;
  }


  function approveTransaction() {
    approvalCount += 1;

    if (approvalCount == 3) {

      mint(msg.sender, 1);
      kill();
    }
  }

  function kill() onlyOwner() {
    selfdestruct(owner);
  }

}

This Relay contract gets created by a separate contract. I run through everything in the truffle console and on the 3rd approveTransaction call I get the following:

truffle(development)> relay.approveTransaction()
Error: VM Exception while processing transaction: invalid opcode
at Object.InvalidResponse     (/usr/local/lib/node_modules/truffle/build/cli.bundled.js:37312:16)
at /usr/local/lib/node_modules/truffle/build/cli.bundled.js:220420:36
at /usr/local/lib/node_modules/truffle/build/cli.bundled.js:204149:9
at XMLHttpRequest.request.onreadystatechange (/usr/local/lib/node_modules/truffle/build/cli.bundled.js:205574:13)
at XMLHttpRequestEventTarget.dispatchEvent (/usr/local/lib/node_modules/truffle/build/cli.bundled.js:73069:18)
at XMLHttpRequest._setReadyState (/usr/local/lib/node_modules/truffle/build/cli.bundled.js:73359:12)
at XMLHttpRequest._onHttpResponseEnd (/usr/local/lib/node_modules/truffle/build/cli.bundled.js:73514:12)
at IncomingMessage.<anonymous> (/usr/local/lib/node_modules/truffle/build/cli.bundled.js:73474:24)
at emitNone (events.js:91:20)
at IncomingMessage.emit (events.js:185:7)

Not really sure why this is happening. At first I thought it was because of the onlyMinter, but that wasn't it. The minted tokens are supposed to go to some arbitrary address. Any ideas? Thank you.