custom configuration sections

i have a custom configuration file called appFollow.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
<section name="DPAFOLLOWUPTOOL" type="System.Configuration.SingleTagSectionHandler" />
</configSections>

<DPAFOLLOWUPTOOL
sqlServer="ELSQLSRV1"
sqlDB="DPA_FollowUp"
networkDir="\\elntsrv4\apps\PRP\DPA FollowUp\" />

</configuration>

i read the sqlServer, sqlDB and networkDir values in the following class:

Imports System.Configuration
Imports System.Collections
Public Class clsConfig

Public Sub GetConfigurations()
Dim appTable As IDictionary

appTable = CType(ConfigurationSettings.GetConfig("DPAFOLLOWUPTOOL"), IDictionary)
modFollow.configSQLServer = CType(appTable("sqlServer"), String)
modFollow.configSQLDB = CType(appTable("sqlDB"), String)
modFollow.configNetworkDir = CType(appTable("networkDir"), String)
End Sub

End Class

but i get the following error where i try to get the first value - "sqlServer"

An unhandled exception of type 'System.NullReferenceException' occurred in DPAFollow.exe

Additional information: Object reference not set to an instance of an object.

it's as if it's not reading anything from my config file.
is there somehwhere that i have to specify my config file?
any other ideas?

thanks