Error #1088: The markup in the document following the root element must be well-formed

Question

So i made button and it wont work cause the problem. I do not know what to do :( I am making simple button app

two problems for now if i delete <?xml version="1.0" encoding="utf-8"?>

the other problems comes up

Description Resource Path Location Type The processing instruction target matching "[xX][mM][lL]" is not allowed. AndroidManifest.xml /Seiklemine line 29 Android XML Format Problem

And my xml is:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.mkyong.android"
  android:versionCode="1"
  android:versionName="1.0" >

  <uses-sdk android:minSdkVersion="10" />             
  <application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name" >             
    <activity
      android:label="@string/app_name"
      android:name=".AppActivity" >
        <intent-filter >
          <action android:name="android.intent.action.MAIN" />
          <category android:name="android.intent.category.LAUNCHER" />          
        </intent-filter>
    </activity>
    <activity
      android:label="@string/app_name"
      android:name=".AppActivity4" >
    </activity>
  </application>
</manifest>