amazon s3 authorization header invalid

I am having problems with amazon s3 authentication.

and the error is pointing to amazon authorization. it says.

AWS authorization header is invalid. Expected AwsAccessKeyId:signature

here us my code:

   // set default values for optional params first
    bucket = bucket || null;
    path = path || '/';
    query = query || [];
    data = data || null;
    headers = headers || [];
    amazon = amazon || null;

    //get host - bucket1.s3.amazonaws.com
    var host    = this._getHost(bucket);
    //get url - http://ift.tt/1CrfP6G
    var url     = this._getUrl(host, path, query);
    //get path - /bucket1/some/path
    var path    = this._getPath(bucket, path);

    hashed().ksort(amazon);

    // initiatialize variables needed
    var restHeaders = amazonHeaders = [];

    headers.Host = host;
    headers.Date = time().toDate(Date.now(), 'D, d M Y H:i:s T', true);

    for (var header in amazon) {
        restHeaders.push(header+': '+amazon[header]);
        amazonHeaders.push(header.toLowerCase()+':'+amazon[header]);
    }

    for (var header in headers) {
        restHeaders.push(header+': '+headers[header]);
    }

    amazonHeaders = '\n'+amazonHeaders.join('\n');

    if(!amazonHeaders.trim()) {
        amazonHeaders = null;
    }

    if(!(typeof headers['Content-MD5'] !== 'undefined')) {
        headers['Content-MD5'] = null;
    }

    if(!(typeof headers['Content-type'] !== 'undefined')) {
        headers['Content-Type'] = null;
    }

    //get signature
    var signature = [
        action,
        headers['Content-MD5'], 
        headers['Content-Type'],
        headers['Date']+amazonHeaders,
        path];

    signature = signature.join('\n');
    if(headers.Host == 'cloudfront.amazonaws.com') {
        signature = headers.Date;
    }

    restHeaders.push('Host: '+host);
    restHeaders.push('Date: '+headers.Date);
    restHeaders.push('Authorization: '+this._getSignature(signature));

please help me, I am forever stuck to this.