Android :: Inserting Records In SQLite

This is my SimpleDBAdapter Class that encapsulates all the complexities of accessing the database and the inner class SimpleDBHelper takes care of CRUD operations,now the Problem that i am facing here is when i deploy the code, the tables were getting created, but the
i am unable to insert tht values in to the table, the id is returning -1 that depicts that there is an error,while inserting the values.

id = db.insert(TABLE_SIMPLETABLE_CLIENT1,null,contentvalues);
SimpleDBAdapter.java
import android.content.ContentValues;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import android.view.ViewGroup.MarginLayoutParams;
public class SimpleDBAdapter {................................