Error in sqlite query help me

public String matchEmail(String email) { String item=null;

        String query="SELECT " + KEY_EMAIL+ " FROM " + TABLE_Register + " WHERE " + KEY_EMAIL +" = '"+email+"'";

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(query, null);
    item= cursor.getString(1);
    return item;
}

//Error Code 02-02 13:53:41.974: E/TAG(1854): Exception: android.database.sqlite.SQLiteException: no such table: Register: , while compiling: SELECT email FROM Register WHERE email = 'rrrr@gmail.com'