Configuration error at compile-time

Hello all:
I have a small class, the project file references the system.dll, the
class imports System.Configuration. There is a line in the class which
states:

Dim test As String =
System.Configuration.ConfigurationSettings.AppSettings.Get("test")

At compile time, I am getting the following error:

error BC30456: 'Configuration Settings is not a member of
'Configuration'.

Now, in the IDE, the design-time compiler checking is quite happy with
the code, and the code completion fuzzies display ConfigurationSettings
for me just fine.

Any thoughts?
Thanks much,
zdrakec