>I don't either - the only thing that I focussed on was from another thread - something like a null reference

Yes, that is correct.


>So I thought that maybe he was setting the property to null, and afterwards reinitialize it
>I have focussed on that - never let the property become null

I think the only thing I had to do was to create another line such as this:

        ' Data dictionary
        Public Tables As New Tables
        Public TablesTemp As New Tables

...and not create another NameObjectCollectionBase under a different names. Then, from the reload, I clear TablesTemp, reload it and assign it to Tables such as:

        ' Load the data dictionary
        Public Function LoadDataDictionary() As Boolean

            ' Make sure to clear all the tables. As when there is a flag to reload the
            ' data dictionary, we need to make sure we reset the collection.
            oApp.TablesTemp.Clear()

            ' Copy the TablesTemp into Tables
            ' This allows a hit in progress to continue as is with this shared oApp object as we used a temporary place holder
            ' during its initialization. Otherwise, a hit in progress may end up with an object reference not found. This was
            ' happening before as it takes about 1.3 seconds to reload the data dictionary.
            oApp.Tables = oApp.TablesTemp

            ' Let the framework know that we are done
            ' This will only happen at startup as there is no need to turn this off on reload
            App.lTables = True

            Return True
        End Function

This is only a partial content of the method. Of course, after the Clear() is all the setup of oApp.TablesTemp.

This seems to work on the first hit and all other hits to the same worker process. I just need to find out why the other worker process are not properly working. But, this seems to work. I will confirm later on once I fine tune the reason for the other situation.