Android app crashes on startActivity

I downloaded a database from the internet and i'm trying to build my app on top of it. It's tested and it works. The problems begin when I try to open a new activity

I have a button called "New" on my main layout which is supposed to open a new window in my app (just open a new activity for now), but it crashes immediately on call. My current activity is DatabaseExampleActivity(my main) and I want the new one to be NewAssignmentActivity.

Here are the relevant code sections:

//the function that is called when "new" button is pressed

public void newAssignment(View view) {
    Intent i = new Intent(DatabaseExampleActivity.this, NewAssignmentActivity.class);
    startActivity(i);
    }

//The manifest

<activity
android:name=".DatabaseExampleActivity"
android:label="@string/app_name" >
<intent-filter>
   <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".NewAssignmentActivity"
        android:label="@string/title_activity_new_assignment" >
    </activity>

//the new activity code

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class NewAssignmentActivity extends ActionBarActivity {

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

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.new_assignment, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

}

consol writes in red : ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.anotherandroidblog.tools.database/.DatabaseExampleActivity }
ActivityManager: Warning: Activity not started, its current task has been brought to the front

The logCat also gives tons of errors too