Eu recebo uma "incompatibilidade de tipo de dados na expressão de critérios". erro ao executar este código em um banco de dados, mas funciona perfeitamente em outro banco de dados. Ao tentar copiar a tabela relevante para outro banco de dados e executá-lo a partir dele, o programa falha novamente!

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Project
{
public partial class Login : Form
{
    public Login()
    {
        InitializeComponent();
    }

    private void Login_Load(object sender, EventArgs e)
    {

    }

    private void label1_Click(object sender, EventArgs e)
    {

    }

    private void LoginButton_Click(object sender, EventArgs e)
    {
        DAL conn = new DAL(@"|DataDirectory|\ProjectDB.accdb");
        DataSet ds = conn.GetDataSet("Select * from Secretarys where SecretaryUsername = "+UserNameBox.Text.ToString());
        if (ds.Tables[0].Rows[0][0].ToString().Equals(PassowrdBox.Text))
            MessageBox.Show("asd","sdfa");
    }
}
}

A classe "DAL" que estou usando.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.OleDb;

/// <summary>
/// Summary description for DAL
/// </summary>
public class DAL
{
private string dbPath;
private OleDbConnection conn;
private OleDbCommand command;
private OleDbDataAdapter adapter;
private string stQuery;

public DAL(string dbPath)
{
    this.dbPath = dbPath;
    string ConnectionString = string.Format(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0}", this.dbPath);
    conn = new OleDbConnection(ConnectionString);
    command = new OleDbCommand(stQuery, conn);
    adapter = new OleDbDataAdapter(command);
}

public DataSet GetDataSet(string strSql)
{
    DataSet ds = new DataSet();
    command.CommandText = strSql;
    adapter.SelectCommand = command;
    adapter.Fill(ds);
    return ds;
}
public bool InsertRow(string sqlInsert)
{
    int rowsEffected;
    command.CommandText = sqlInsert;
    conn.Open();
    rowsEffected = command.ExecuteNonQuery();
    conn.Close();
    return (rowsEffected > 0);

}

public string GetData(string strSql)//שולפת נתונים מהטבלת המשתמשים שנמצאת באקסס
{
    string st = "";
    DataSet ds = new DataSet();
    command.CommandText = strSql;
    conn.Open();
    st = command.ExecuteScalar().ToString();
    conn.Close();
    return (st);
}

public void UpdateRow(string sqlInsert)//הוספת נתונים לטבלת החברים באקסס
{

    command.CommandText = sqlInsert;
    conn.Open();
    command.ExecuteNonQuery();
    conn.Close();

}
public void DeleteDataSet(DataSet ds)
{

    OleDbCommandBuilder builder = new OleDbCommandBuilder(adapter);
    adapter.DeleteCommand = builder.GetDeleteCommand();
    conn.Open();
    adapter.Update(ds);
    conn.Close();
}
}