"Unspecified error" when opening a database

[fniles]

I am using VB.Net 2003 and MS Access database. Sometimes when I open the
database, I got the error "Unspecified error"
The application validate users, when it validates users, it reads from a
table in the database. I use connection pooling by opening the database in
Form_Load, then everytime somebody comes in, I open the database and reads
from it to validate the user. I then close the database.
How can I fix this "Unspecified error" ?
Thank you.

Function ValidateDemoUser(ByVal lIndex As Long, ByRef Packet As String,
ByVal sAccount As String, ByRef Connection As SqlClient.SqlConnection, ByRef
ConnectionOLE As OleDb.OleDbConnection, ByRef ConnectionDemo As
SqlClient.SqlConnection, ByRef ConnectionDemoOLE As OleDb.OleDbConnection)
As String
Dim sql As String
Dim bDBSuccess As Boolean
Dim cmd As New OleDb.OleDbCommand
Dim da As OleDb.OleDbDataAdapter
Dim ds As DataSet

sql = "select * from CUSTOMER where ACCOUNT = '" & sAccount & "'"
With cmd
bSuccess = True
bDBSuccess = OpenDBDemoOLE(ConnectionDemoOLE)
If bDBSuccess Then
.Connection = ConnectionDemoOLE
.CommandText = sql
da = New OleDb.OleDbDataAdapter
ds = New DataSet
da.SelectCommand = cmd
da.Fill(ds)
CloseConDemoOLE(ConnectionDemoOLE)
:

Sub CloseConDemoOLE(ByRef ConnectionDemoOLE As OleDb.OleDbConnection)
If Not ConnectionDemoOLE Is Nothing Then
ConnectionDemoOLE.Close()
ConnectionDemoOLE = Nothing
End If
End Sub

Function OpenDBDemoOLE(ByRef ConnectionDemoOLE As OleDb.OleDbConnection)
As Boolean
Dim swError As StreamWriter
Dim sSub As String

Try
sSub = "1"
ConnectionDemoOLE = New OleDb.OleDbConnection
OpenDBDemoOLE = True
With ConnectionDemoOLE
.ConnectionString = g_dbPathDemo
sSub = "2"
.Open() '--error "Unspecified error"
sSub = "3"
If .State = ConnectionState.Closed Then
sSub = "4"
CloseConDemoOLE(ConnectionDemoOLE)
sSub = "5"
OpenDBDemoOLE = False
End If
End With
Catch ex As Exception
OpenDBDemoOLE = False
swError = New StreamWriter(Application.StartupPath &
"\AQErrorLog" & Date.Now.ToString("MMddyy") & ".txt", True)
swError.Write(Now & " OpenDBDemoOLE - error = " & ex.Message
& " sub = " & sSub & vbCrLf)
swError.Close()
swError = Nothing
End Try
End Function