Activity not defined

I have been trying to implement ads for which I have chosen to use leadbolt service but when I try to load ads it gives me error" Ad failed to load - activity not defined", I tried my best to find out where it needs to be defined but I couldn't. Please help me out this time and I know that startsession is deprecated. Here is my activity

public class TopRatedFragment extends Fragment {
private ProgressBar progress;
private WebView myWebView2;
private Menu optionsMenu;
private static final String APP_API_KEY         = "xxxxxxxxxxx";
private static final String LOCATION_CODE       = "inapp";

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         final Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_top_rated, container, false);


    String url = "http://example.com";
    myWebView2 = (WebView) rootView.findViewById(R.id.webViewTop);
    myWebView2.setWebChromeClient(new myWebViewClient());
    myWebView2.getSettings().setJavaScriptEnabled(true);
    progress = (ProgressBar) rootView.findViewById(R.id.progressBar3);
    progress.setMax(100);
    setHasOptionsMenu(true);



    if(savedInstanceState == null) {
        AppTracker.setModuleListener(leadboltListener);
        // Initialize Leadbolt SDK
        //deprecated
        AppTracker.startSession(getActivity(), APP_API_KEY);
        myWebView2.loadUrl(url);
    }

    myWebView2.setWebViewClient(new WebViewClient() {

        @Override
        public boolean shouldOverrideUrlLoading(WebView View, String url) {
            View.loadUrl(url);
            TopRatedFragment.this.progress.setProgress(0);
            return true;
        }

    });
    myWebView2.setOnKeyListener(new android.view.View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (event.getAction() == KeyEvent.ACTION_DOWN) {
                WebView webView = (WebView) v;

                switch (keyCode) {
                    case KeyEvent.KEYCODE_BACK:
                        if (webView.canGoBack()) {
                            webView.goBack();
                            return true;
                        }
                        break;
                }
            }

            return false;
        }
    });
    return rootView;

}
public AppModuleListener leadboltListener = new AppModuleListener() {
    @Override
    public void onModuleCached(final String placement) {
        Toast.makeText(getActivity(), "Ad successfully cached - " + placement, Toast.LENGTH_SHORT).show();
        // Ad has been cached, now enable the Show Ad button
    }
    @Override
    public void onModuleClicked(String placement) {
        Toast.makeText(getActivity(), "Ad clicked", Toast.LENGTH_SHORT).show();
    }
    @Override
    public void onModuleClosed(String placement) {
        Toast.makeText(getActivity(), "Ad closed", Toast.LENGTH_SHORT).show();
    }
    @Override
    public void onModuleFailed(String placement, String error, boolean isCache) {
        if(isCache) {
            Toast.makeText(getActivity(), "Ad failed to cache - "+error, Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(getActivity(), "Ad failed to load - "+error, Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onModuleLoaded(String placement) {
        Toast.makeText(getActivity(), "Ad displayed", Toast.LENGTH_SHORT).show();
        // Ad has been shown, now disable to the Show Ad button

    }
    @Override
    public void onMediaFinished(boolean viewCompleted) {}
};


private class myWebViewClient extends WebChromeClient {
    @Override

    public void onProgressChanged(WebView view, int newProgress) {

        super.onProgressChanged(view, newProgress);


        progress.setProgress(newProgress);
        //loadingTitle.setProgress(newProgress);
        // hide the progress bar if the loading is complete

        if (newProgress == 100) {
            progress.setVisibility(View.GONE);
            setRefreshActionButtonState(false);
          // here i try to display ads.                
          AppTracker.loadModule(getActivity(), LOCATION_CODE);

        } else{
            progress.setVisibility(View.VISIBLE);

        }

    }

}}

Thanks for your time.