加载字体时“运行时异常：无法创建本机字体”

我正在尝试在Android上使用自定义字体作为TextView，请按照此处的指南进行操作。使用相同的字体，相同的代码，相同的一切，我在adb logcat中得到这个：

W/dalvikvm(  317): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
E/AndroidRuntime(  317): FATAL EXCEPTION: main
E/AndroidRuntime(  317): java.lang.RuntimeException: Unable to start activity  ComponentInfo{org.evilx.quacklock/org.evilx.quacklock.MainActivity}:             java.lang.RuntimeException: native typeface cannot be made
E/AndroidRuntime(  317):        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
E/AndroidRuntime(  317):        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
E/AndroidRuntime(  317):        at android.app.ActivityThread.access$2300(ActivityThread.java:125)
E/AndroidRuntime(  317):        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
E/AndroidRuntime(  317):        at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(  317):        at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime(  317):        at android.app.ActivityThread.main(ActivityThread.java:4627)
E/AndroidRuntime(  317):        at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(  317):        at java.lang.reflect.Method.invoke(Method.java:521)
E/AndroidRuntime(  317):        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
E/AndroidRuntime(  317):        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
E/AndroidRuntime(  317):        at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime(  317): Caused by: java.lang.RuntimeException: native typeface cannot be made
E/AndroidRuntime(  317):        at android.graphics.Typeface.<init>(Typeface.java:147)
E/AndroidRuntime(  317):        at android.graphics.Typeface.createFromAsset(Typeface.java:121)
E/AndroidRuntime(  317):        at org.evilx.quacklock.MainActivity.onCreate(MainActivity.java:24)
E/AndroidRuntime(  317):        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
E/AndroidRuntime(  317):        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
E/AndroidRuntime(  317):        ... 11 more
W/ActivityManager(   59):   Force finishing activity org.evilx.quacklock/.MainActivity
W/ActivityManager(   59): Activity pause timeout for HistoryRecord{43e80368 org.evilx.quacklock/.MainActivity}
D/dalvikvm(  247): GC_EXPLICIT freed 711 objects / 53160 bytes in 20922ms

我使用的字体Molot.otf，它在其中一个博客中成功使用。我还使用predpred.ttf，这是另一种自定义字体，但采用TrueType格式。

相关代码：

public class MainActivity extends Activity {
    // Called when the activity is first created.
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        Typeface tf = Typeface.createFromAsset(getAssets(), "fonts/Molot.otf");
        TextView tv = (TextView) findViewById(R.id.CustomFontText);
        tv.setTypeface(tf);
    }
}

和

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView
        android:id="@+id/CustomFontText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="Here is some text.">
    </TextView>
</LinearLayout>

这是什么原因造成的？它适用于博客中的人，那么为什么不是我呢？API 中是否有重大更改阻止我执行此操作？