Error: Incorrect header check with node.js

Question

So I have a bit of a problem, and I couldn't figure out a way to solve it. I have a 'webserver' written in node.js and one of its functions is to log and encrypt the client IP. Whenever I then run it and access it, It ends up giving me this error:

Error: incorrect header check
at Zlib._handle.onerror (zlib.js:370:17)

And I'm really stuck.

Here's the full code:

var http       = require('http');
var fs         = require('fs');
var express    = require('express');

var app        = express();

function process(arg) {
  console.log(arg);
}

function EncryptIP() {
  var crypto = require('crypto');
  var fs     = require('fs');
  var zlib   = require('zlib');

  var password = new Buffer('__Password__');
  var encrypt  = crypto.createCipher('aes-256-cbc', password);

  var gzip        = zlib.createGzip();
  var writeStream = fs.createWriteStream("../../Website/IP Logs/IP Log");
  var readStream  = fs.createReadStream("../../Website/IP Logs/IP Log");

  readStream
    .pipe(encrypt)
    .pipe(gzip)
    .pipe(writeStream)
    .on('finish', function () {
      console.log('Encryption: Finished Encrypting');
      console.log(' ');
    });
}

function DecryptIP() {
  var crypto = require('crypto');
  var fs     = require('fs');
  var zlib   = require('zlib');

  var password = new Buffer('__Password__');
  var decryptStream = crypto.createDecipher('aes-256-cbc', password);

  var gzip = zlib.createGunzip();
  var readStream1 = fs.createReadStream('../../Website/IP Logs/IP Log');

  console.log('');

  readStream1   // reads current files
    .pipe(gzip)  // uncompresses
    .pipe(decryptStream) // decrypts
    .on('finish', function () {  // finished
      console.log('Completed Decrypting');
      console.log(' ');
    });

}



app.get('/', function(req, res) {
  console.log("Webpage Requested");

  var Filedata;

  var fileReadStream = fs.createReadStream('../Webpages/index.html');

  fileReadStream
    .on('open', function () {
      fileReadStream.pipe(res);
    });
  fileReadStream
    .on('error', function (err) {
      res.send(err);
    });


  var ip = req.connection.remoteAddress;
  console.log("Logging their IP Address... IP: " + ip);

  fs.readFile("../../Website/IP Logs/IP Log", function(err, data) {
    DecryptIP();
    if(err) {
      process(err);
    }

    filedata  = data + '\n' + ip;

    fs.writeFile("../../Website/IP Logs/IP Log", filedata, function(err) {
      if(err) {
          process(err);
      }

      console.log("Log: IP saved...");
    });
  });

  console.log("Encrypting their IP Address...");
  EncryptIP();
});

app.get('/Admin%20Tools', function(req, res) {
  res.send("<style>h2 {color: red;}</style><h2>Access Denied!</h2>");
  console.log("Webpage Requested");

  var ip = req.connection.remoteAddress;
  console.log("Logging their IP Address... IP: " + ip);

  fs.readFile("../../Website/IP Logs/IP Log", function(err, data) {
    DecryptIP();
    if(err) {
      process(err);
    }

    filedata  = data + '\n' + ip;
    fs.writeFile("../../Website/IP Logs/IP Log", filedata, function(err) {
      if(err) {
          process(err);
      }

      console.log("Log: IP saved...");
    });

    var fileStream = fs.createWriteStream('../../Website/IP Logs/IP Log');

    console.log("Encrypting their IP Address...");
    EncryptIP();
  });
});

app.get('/IP%20Logs', function(req, res) {
  res.send("<style>h2 {color: red;}</style><h2>Access Denied!</h2>");
  console.log("Webpage Requested");

  var ip = req.connection.remoteAddress;
  console.log("Logging their IP Address... IP: " + ip);

  fs.readFile("../../Website/IP Logs/IP Log", function(err, data) {
    DecryptIP();
    if(err) {
      process(err);
    }

    filedata  = data + '\n' + ip;

    fs.writeFile("../../Website/IP Logs/IP Log", filedata, function(err) {
      if(err) {
          process(err);
      }

      console.log("Log: IP saved...");
    });

    console.log("Encrypting their IP Address...");
    EncryptIP();
  });
});

app.get('/Webpages', function(req, res) {
  res.send("<style>h2 {color: red;}</style><h2>Access Denied!</h2>");
  console.log("Webpage Requested");

  var ip = req.connection.remoteAddress;
  console.log("Logging their IP Address... IP: " + ip);

  fs.readFile("../../Website/IP Logs/IP Log", function(err, data) {
    DecryptIP();
    if(err) {
      process(err);
    }

    filedata  = data + '\n' + ip;

    fs.writeFile("../../Website/IP Logs/IP Log", filedata, function(err) {
      if(err) {
          process(err);
      }

      console.log("Log: IP saved...");
    });

    console.log("Encrypting their IP Address...");
    EncryptIP();
  });
});

app.get('/Webserver', function(req, res) {
  res.send("<style>h2 {color: red;}</style><h2>Access Denied!</h2>");
  console.log("Webpage Requested");

  console.log("Logging their IP Address...");
  var ip = req.connection.remoteAddress;

  fs.readFile("../../Website/IP Logs/IP Log", function(err, data) {
    DecryptIP();
    if(err) {
      process(err);
    }

    filedata  = data + '\n' + ip;

    fs.writeFile("../../Website/IP Logs/IP Log", filedata, function(err) {
      if(err) {
          process(err);
      }

      console.log("Log: IP saved...");
    });

    console.log("Encrypting their IP Address...");
    EncryptIP();
  });
});

app.listen(8000);