关于composer报错 [ 2.0 版本 ]

包的地址：

https://packagist.org/packages/newerton/yii2-fancybox

github地址：

github.com/newerton/yii2-fancybox

包的说明：

php: >=5.4.0
yiisoft/yii2: *
bower-asset/fancybox: @stable
bower-asset/jquery-mousewheel: ~3.1.3

我的 composer.json 文件写入如下：

    "require": {
        "php": ">=5.4.0",
        "yiisoft/yii2": ">=2.0.4",
        "yiisoft/yii2-bootstrap": "*",
        "yiisoft/yii2-swiftmailer": "*",
        "kartik-v/yii2-widget-datepicker": "dev-master",
        "bower-asset/fancybox": "@stable",
        "bower-asset/jquery-mousewheel": "~3.1.3"
    },

composer install之后：

Loading composer repositories with package information
Installing dependencies <including require-dev>
Your requirements could not be resolved to an installable set of packages.

	Problem 1
		- The requested package bower-asset/fancybox could not be found in any version, there may be a typo in the package name.
	Problem 2
		- The requested package bower-asset/jquery-mousewheel could not be found in any version, there may be a typo in the package name.

Potential causes:
	- A typo in the package name
	- The package is not available in a stable-enough version according to your minimum-stability setting

		see <https://groups.google.com/d/topic/composer-dev/_g2ASeIFlrc/discussion> for more details.

Read <http://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.		

我想知道，为什么出这个错误以及怎么解决？不胜感谢！