ADO.NET Specified cast is not valid

[ralaing]

Specified cast is not valid.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidCastException: Specified cast is not valid.

Source Error:

Line 12: Public Sub AddCart(ByVal CustomerID As Integer, ByVal ProductID As Integer, ByVal Qty As Integer)
Line 13: 'Add a single row item to the cart
Line 14: Dim objCmd As New OleDbCommand("uspAddCart", objConn)
Line 15: objCmd.CommandType = CommandType.StoredProcedure
Line 16:

Problem is line 14, but why? Everything was working - now it isn't! What might I have done?

Connection info:
Dim configurationAppSettings As System.Configuration.AppSettingsReader = New System.Configuration.AppSettingsReader

Private objConn = CType(configurationAppSettings.GetValue("DSN", GetType(System.String)), String)

...and in Web.config:
<add key="DSN" value="Provider=Microsoft.Jet.OleDB.4.0;Data Source=c:\files\access\data\ProvidenceData.mdb" />

[Tekmaven]

Private objConn = CType(configurationAppSettings.GetValue("DSN", GetType(System.String)), String)

objConn as no variable type...?

[ralaing]

objConn as no variable type...?

Sorry, still trying to get a handle on this stuff. If the following works for an SQL connection, why doesn't similar code work for oleDB?

Private objConn As SqlConnection
Private objCmd As SqlCommand
Private dsn As String = ConfigurationSettings.AppSettings("dsn")

Public Function GetSingleTaskObs(ByVal intObservationID As Integer) As SqlDataReader
'Get Base observation details for a given ObservationID
Try
objConn = New SqlConnection(dsn)
objCmd = New SqlCommand("usp_GetObservation", objConn)
objCmd.CommandType = CommandType.StoredProcedure