出错，不知道怎么解决。

10-26 13:02:11.983: ERROR/AndroidRuntime(475): java.lang.RuntimeException: Unable to resume activity {com.mp3player/com.mp3player.LocalMp3ListActivity}: java.lang.NullPointerException
这是空指针异常？
AndroidManifest.xml文件内容
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mp3player"
    android:versionCode="1"
    android:versionName="1.0" > 
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".MainActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".Mp3ListActivity" android:label="@string/app_name"/>
        <activity android:name=".LocalMp3ListActivity" android:label="@string/app_name"/>
        <service android:name="com.service.DownLoadService"></service>
    </application>
    <uses-sdk android:minSdkVersion="8" />
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/></manifest>
应该是这段代码的问题：
protected void onResume() {
FileUtils fileUtils = new FileUtils();
List<Mp3Info> mp3infos = fileUtils.getMp3Files("mp3/");
List<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>();
for(Iterator iterator = mp3infos.iterator();iterator.hasNext();){
Mp3Info mp3info = (Mp3Info)iterator.next();
HashMap<String,String> map = new HashMap<String,String>();
map.put("mp3_name", mp3info.getMp3Name());
map.put("mp3_size", mp3info.getMp3Size());
list.add(map);
    }
SimpleAdapter simpleAdapter = new SimpleAdapter(this,list,R.layout.mp3info_item,new String[]{"mp3_name","mp3_size"},new int[]{R.id.mp3_name,R.id.mp3_size});
setListAdapter(simpleAdapter);
super.onResume();
}