VB.Net does some weird things at times, you could put a Try - Catch structure around it. Run it after that and see if it is working or not (you should be able to tell right off).
Like this:
Try
Dim x As New MfgControl.AdvancedHMI.Drivers.Common.PlcComEventArgs(New String() {ex.Message}, PolledAddressList(i).Address.Address, 0)
Catch ex1 as Exception
Then look at ex1.message to see what (if anything) the exception was.