Download and Extract Zip File in Android

My application is downloading zip file from the server and extract this zip file and save files into sd card but problem is if i am downloading 4-5 MB zip files and extract it, this is working good but if i am downloading 30-35 MB zip file this will give me error, sorry for my bad English communication.

The Below is my Code for Download & Unzip Zip File:-

public class UnzipManager {
    private static String BASE_FOLDER;

    public static Context localContext;
    public static String passurl;
    public static int count;
    public static Context context;
    /*
     * You can use this flag to check whether Unzippingthread is still running..
     */
    public static boolean isDownloadInProgress;
    /*
     * After unzipping using this flag ,you can check whether any low memory
     * exceptions Occurred or not..and alert user accordingly..
     */
    public static boolean isLowOnMemory;
    public static int i = 0;

    public static ZipEntry zipEntry;

    public static void startUnzipping(Context ctx, int c, String url) {
        context = ctx;
        count = c;
        /*
         * MAKE SURE THAT localContext VARIABLE HAS BEEN INITIALIZED BEFORE
         * INVOKING THIS METHOD.
         * 
         * ALSO MAKE SURE YOU HAVE SET "INTERNET" AND "NETWORK ACCESS STATE"
         * PERMISSIONS IN APPLICATION'S MANIFEST FILE.
         */
        Log.d("DEBUG", "In startUnzipping()");
        UnzipManager.BASE_FOLDER = Environment.getExternalStorageDirectory()
                + File.separator + "samples";
        /*
         *
         */

        Log.d("DEBUG", "BASE_FOLDER:" + UnzipManager.BASE_FOLDER);
        UnzipManager.isLowOnMemory = false;
        // Start unzipping in a thread..which is safer
        // way to do high cost processes..
        passurl = url;
        new UnzipThread().start();
    }

    private static class UnzipThread extends Thread {
        @Override
        public void run() {
            UnzipManager.is