Android programozásban kellene segítség (? )

Van egy kódrészlet, ami hibát dob, csak nem tudom miért. Elvben helyes, de nem működik...

public class MySQLiteAdapter {

MySQLite sql;

Context context;

public MySQLiteAdapter(Context context) { //constructor

sql = new MySQLite(context);

this.context=context;

}

public long insertUser(String Username,String Pass, String Name, String Mail){

SQLiteDatabase db=sql.getWritableDatabase();

ContentValues cv=new ContentValues();

cv.put(MySQLite.COLUMN_USERNAME,Username);

cv.put(MySQLite.COLUMN_PASSWORD,Pass);

cv.put(MySQLite.COLUMN_REALNAME,Name);

cv.put(MySQLite.COLUMN_MAIL,Mail);

long id=db.insert(MySQLite.TABLE_USERS,null,cv);

return id;

}

class MySQLite extends SQLiteOpenHelper {

private static final String DATABASE_NAME = "APPLICATION"; //name database

private static final int DATABASE_VERSION = 2;

public static final String TABLE_USERS="users_table";

public static final String COLUMN_ID = "_id";

public static final String COLUMN_USERNAME="USERNAME";

public static final String COLUMN_PASSWORD="PASSWORD";

public static final String COLUMN_REALNAME="NAME";

public static final String COLUMN_MAIL="E-MAIL";

private static final String TABLE_CREATE_USERS="CREATE TABLE "+TABLE_USERS+"("+COLUMN_ID

+"INTEGER PRIMARY KEY AUTOINCREMENT, "

+COLUMN_USERNAME+"VARCHAR(250) NOT NULL, "+COLUMN_PASSWORD+"VARCHAR(250) NOT NULL, "

+COLUMN_REALNAME+"VARCHAR(250) NOT NULL, "+COLUMN_MAIL+"VARCHAR(250) NOT NULL );";

//Szerintem itt a hiba

private static final String DROP_TABLE_USERS="DROP TABLE IF EXISTS "+TABLE_USERS;

public MySQLite(Context context) {

super(context, DATABASE_NAME, null, DATABASE_VERSION);

Message.mess(context,"CONSTRUCTOR WAS CALLED ");

}

@Override

public void onCreate(SQLiteDatabase db) {

try {

db.execSQL(TABLE_CREATE_USERS);

Message.mess(context,"USERS TABLE WAS CREATED");

} catch (SQLException e) {

Message.mess(context,"ERROR CREATING TABLE "+e); //Itt adja a hiba uzenetet

}

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

db.execSQL(DROP_TABLE_USERS);

Message.mess(context,"UPGRADE WAS CALLED");

onCreate(db);

}

}//end of inner class

}

a Message.mess egy Toast-ot ir ki a hibaval vagy a sikeres muveletet megerosito uzenettel