Check the dbcomm.parameters.cout property beofre calling the command. Probably, you do not have the required number. Something could be wrong in your analyser of line.

Note also that Parameters(5) and (6) have the same name.

Make sure all of the column names in your table are spelled correctly and match the names specified in the SQL query. Also, be cautious about using reserved words such as "memo".

I'm not sure whether the duplicate parameter name would cause the problem, as mentioned by the other poster, because these are ignored by the .NET OLEDB provider, but it wouldn't hurt to change it to the correct value (e.g. streetname2).

Where are all of these Parameter Count values coming from? I was only looking for the Parameter Count, for the query in your code, when the exception is generated.

Are you reusing the dbComm object instance?

Don't forget to assign DBNull.Value to parameters that you're not using. For example, if you had a 'FirstName' parameter, but you didn't want to specify a value for it, be sure to assign it DBNull.Value instead of Nothing.

Dim firstName As String = Nothing

MyCommand.Parameters("FirstName").Value = DBNull.Value

'instead of

MyCommand.Parameters("FirstName").Value = firstName

The code in the 'Else' block looks good. However, in your 'If' block, the statement 'DBNull.Value.ToString()' will not work because it will evaluate to a String object. DBNull is a different type of object. But your 'Else' looks promising. If it still doesn't work, you may want to try something like this for all of your parameters:

With dbcomm.Parameters
.AddWithValue("@isCustomer", DBNull.Value)
.AddWithValue("@followUp", DBNull.Value)
.AddWithValue("@customerSince", Date.Today().ToString())
.AddWithValue("@salesPerson", DBNull.Value)
.AddWithValue("@companyName", IIf(String.IsNullOrEmpty(line(0)), DBNull.Value, line(0)))
.AddWithValue("@jobTitle", IIf(String.IsNullOrEmpty(line(1)), DBNull.Value, line(1)))
.AddWithValue("@fullName", IIf(String.IsNullOrEmpty(line(2) & " " & line(3) & " " & line(4)), DBNull.Value, line(2) & " " & line(3) & " " & line(4)))
.AddWithValue("@streetName", IIf(String.IsNullOrEmpty(line(5)), DBNull.Value, line(5)))
'... And so on...

End With

The

With dbcomm.Parameters

.AddWithValue("@isCustomer", "False")

End With

Is inside the While loop and therefore you are adding the parameters over and over.

Add the parameters outside the loop (forget the loop) or place is in a sub for optional use.

Validate the string array length.

Add and set the parameters if the array length is valid

and execute the query

Are you of and running?

Public Function AddLine(ByVal ConnectionString As String, ByVal Line() As String) As Integer

' Validate data before bothering to do anything else

' This should really happen before calling this method especially as you are

' using a string array which has no name value association

' All you can do isa check the length

If Line.Length < 22 Then

' Throw New System.Exception("Invalid Line")

Exit Function

End If

Dim Result As Integer = 0

Dim cmd As New OleDbCommand

Dim con As New OleDbConnection

' config connection

' config command

cmd.CommandText = "INSERT INTO [Contactsdb] ([isCustomer], [followUp], [customerSince], [salesPerson], [companyName], [jobTitle], [fullName], [streetName], [streetName2], [cityName], [stateName], [zipCode], [countryName], [telephone], [mobilephone], [fax], [emailAddress], [webpage], [shippingAccount], [creditCard], [cardHolder], [memo])" & _

cmd.Parameters.Add("@ItemID", OleDbType.Integer).Value = Line(ProperIndexinArrayForColumn)

cmd.Parameters.Add("@SecondParam", OleDbType.VarChar).Value = Line(ProperIndexinArrayForColumn)

'...... More Params

'to allow all commands to be nullable

Dim param As OleDbParameter

For Each param In cmd.Parameters

param.IsNullable = True

Next

' Set parameter values

' Option One

cmd.Parameters("@ItemID").Value = Line(0)

cmd.Parameters("@SecondParam").Value = Line(ApproperIndexinArrayForColumn)

' .... more param values

' or

' option two

If Not Line(ApproperIndexinArrayForColumn) = "" Then

cmd.Parameters("@SecondParam").Value = Line(ApproperIndexinArrayForColumn)

End If

' managed execution/ error handling. Very important for the connection.

Try

Catch ex As Exception

con.Dispose() ' closes and disposes

' place break point on cmd.dispose() to easily review exception. Not above! you may stop execution which doesn't terminate the connection and you can be forced into a system restart due to an access db lock.

End Try

Return Result

End Function

or possibly review usage for (instantiate for each line)