Can (this) throws a NullPointerException?

Can (this) throws a NullPointerException?

I have an Activity with checkbox that triggers onCheckedChanged(), and I
initializing it by using.
CheckBox check = (CheckBox) findViewById(R.id.checkbox_accept);
check.setOnCheckedChangeListener(this);
here's the xml.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/linearlayout_welcome_main"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/nce_a1_default_icon_signup_background"
android:orientation="vertical" >
<ScrollView
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:fillViewport="true"
android:isScrollContainer="true"
android:scrollbars="none" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:orientation="vertical"
android:padding="10dp" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1"
android:src="@drawable/nce_a1_default_icon_signup_start" />
<CheckBox
android:id="@+id/checkbox_accept"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|bottom"
android:background="@drawable/checkmarkbox_bg"
android:button="@drawable/nce_a1_default_icon_checkmark_box_selector"
android:paddingBottom="5dp"
android:paddingLeft="25dp"
android:paddingRight="5dp"
android:paddingTop="5dp"
android:text="@string/sign_up_yeah_sure_verify_me"
android:textColor="@color/black_opacity_90"
android:textSize="14sp" />
</LinearLayout>
</ScrollView>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@drawable/nce_a1_default_icon_delete_bar"
android:gravity="center"
android:orientation="horizontal"
android:padding="10dp" >
<Button
android:id="@+id/btn_learn_more"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dp"
android:background="@drawable/nce_a1_default_icon_button_dont_get_it_selector"
/>
<Button
android:id="@+id/btn_continue"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:background="@drawable/nce_a1_default_icon_button_lets_go_selector"
android:enabled="false" >
</Button>
</LinearLayout>
</LinearLayout>
what weird is it works but there is a time that it caused
NullPointerException. Should I use (MainActivity.this) instead of (this)
only? Is there a difference between the two?
one thing I have the same id's in different layout. Should it be the
caused? but I think that is fine because I'm using a View.