setAdapter() in Fragment

public class MainMenu extends FragmentActivity implements ActionBar.TabListener{
    ListView msgList;
    ArrayList<MessageDetails> details;
    AdapterView.AdapterContextMenuInfo info;
    
    
    ProgressDialog progress; 
    private ViewPager viewPager;
    private TabsPagerAdapter mAdapter;
    private ActionBar actionBar;
    
    private String[] tabs = { "Uebersicht", "1", "2"};


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.menu);

        Intent intename = getIntent();
        String uname = (String) intename.getStringExtra("USERNAME");

        msgList = (ListView) findViewById(R.id.MessageList);
        
        details = new ArrayList<MessageDetails>();
            
        MessageDetails Detail;
        Detail = new MessageDetails();
        Detail.setIcon(R.drawable.ic_launcher);
        Detail.setName("Bob");
        Detail.setSub("Dinner");
        Detail.setDesc("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nulla auctor.");
        Detail.setTime("12/12/2012 12:12");
        details.add(Detail);
        
        msgList.setAdapter(new CustomAdapter(details , this));

        
        viewPager = (ViewPager) findViewById(R.id.pager);
        actionBar = getActionBar();
        mAdapter = new TabsPagerAdapter(getSupportFragmentManager());
        
        viewPager.setAdapter(mAdapter);
        actionBar.setHomeButtonEnabled(false);
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 
        
        for (String tab_name : tabs) {
            actionBar.addTab(actionBar.newTab().setText(tab_name)
                    .setTabListener(this));
        }
        
        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
             
            @Override
            public void onPageSelected(int position) {
                // on changing the page
                // make respected tab selected
                actionBar.setSelectedNavigationItem(position);
            }
         
            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
            }
         
            @Override
            public void onPageScrollStateChanged(int arg0) {
            }
        });

.....

10-07 18:02:42.677: W/dalvikvm(6418): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
10-07 18:02:42.707: E/AndroidRuntime(6418): FATAL EXCEPTION: main
10-07 18:02:42.707: E/AndroidRuntime(6418): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.schuldenmanagement/de.schuldenmanagement.MainMenu}: java.lang.NullPointerException
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1955)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.app.ActivityThread.access$600(ActivityThread.java:122)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.os.Looper.loop(Looper.java:137)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.app.ActivityThread.main(ActivityThread.java:4340)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at java.lang.reflect.Method.invokeNative(Native Method)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at java.lang.reflect.Method.invoke(Method.java:511)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at dalvik.system.NativeStart.main(Native Method)
10-07 18:02:42.707: E/AndroidRuntime(6418): Caused by: java.lang.NullPointerException
10-07 18:02:42.707: E/AndroidRuntime(6418):     at de.schuldenmanagement.MainMenu.onCreate(MainMenu.java:92)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.app.Activity.performCreate(Activity.java:4465)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
10-07 18:02:42.707: E/AndroidRuntime(6418):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
10-07 18:02:42.707: E/AndroidRuntime(6418):     ... 11 more