Alright, here's what I'm using.

To import the DLL:

Code:
Module WinInet
    <DllImport("wininet.dll", CharSet:=CharSet.Unicode)> Function InternetSetOption(ByVal hInternet, ByVal dwOption, ByVal lpBuffer, ByVal dwBufferLength)
    End Function

End Module
To use the function that I imported:

Code:
        settingsreturn = InternetSetOption(IntPtr.Zero, INTERNET_OPTION_SETTINGS_CHANGED, IntPtr.Zero, 0)
        refreshreturn = InternetSetOption(IntPtr.Zero, INTERNET_OPTION_REFRESH, IntPtr.Zero, 0)
And it's giving me the error "MarshalDirectiveException was unhandled". What am I doing wrong?