Get error on web application defining a class

Get error only on web.

locally it works fine.

the line is:

dim MIO as new IOM

IOM is a class I defined and resides in App_Code

Here how it starts:

Imports Microsoft.VisualBasic
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.OleDb


Public Class IOM
'Public connectionString As String = "workstation id=TESTDBRB.mssql.somee.com;packet size=4096;user id=renbol1946_SQLLogin_1;pwd=rprlkx4aav;data source=TESTDBRB.mssql.somee.com;persist security info=False;initial catalog=TESTDBRB"

'Public connectionString As String = "Data Source=CASA-VAIO\SQLEXPRESS;Initial Catalog=PROVA;Integrated Security=True"
Public connectionString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=""C:\Users\Casa\Desktop\SOLE\PROGETTO BIBLIO DA VAIO\BIBLIO.accdb"""

Public connection As New OleDbConnection(connectionString)
Public ds As New DataSet
Public ds2 As New DataSet
Public BackupDrive As String
Public returnValue As Long
Public estrazione As Boolean

Sub Seleziona(sqlstr As String, tbl As String)
Dim adaptr As New OleDbDataAdapter()

Try
connection.Open()
adaptr.SelectCommand = New OleDbCommand(sqlstr, connection)
adaptr.SelectCommand.ExecuteNonQuery()

adaptr.Fill(ds, tbl)



connection.Close()

Catch Ex As Exception
MsgBox(Ex.Message, "File Browser")
End Try

End Sub
Sub Seleziona2(sqlstr As String, tbl As String)
Dim adaptr As New OleDbDataAdapter()

Try
connection.Open()
adaptr.SelectCommand = New OleDbCommand(sqlstr, connection)

.......and so on....

Thanks

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