I plan to upload my data to NBN but having trouble with installing NBN Exchange Addin into R6 version 6.25 and Dictionary 3B on a W10 laptop.

First off I made the mistake of downloading and installing NBNExchangeAddin v6.17. It would not work and caused R6 to crash while running a report.  I then realised my mistake and then removed the NBNExchange Addin (at least I thought I had).  Found the NBNExchange Addin ocx file still in C:\Recorder 6\Addins.  Deleted the file there. R6 shut down and restarted. On R6 startup got the message to say that NBNExchange Addin could not be loaded,with a list of the successfully loaded addins . NBN Exchange no longer appeared  in the installed Addins list. Closed R6.

Next I downloaded NBNExchange Addin v6.23 and unzipped it.

Started R6 again.
Tools>Install>Addin Modules then selected. Navigated to NBNExchangeAddinNu.dll and selected it. Message said Addin installed successfully.. The NBNExchange Addin appears in the Addins Configuration List. Clicked OK.  Then got screen warning that "unable to load NBNExchange.NBNExchange Format : The specified module could not be found". Clicked OK.
To see if anything  actually worked, I selected a Survey, then Tools>Export Data. Selected Export Type"NBNExchange Format v6.23" from the Export Type dropdown. Selected a destination for the files. Then clicked OK.  Then got unhandled error message "Specified module could not be found...."
Full text of error message attached

Any idea where I go from here? How do I clear out all aspects of the Addin installation and start again?
I've read Paul Stevens' post of 29/2/2016 but this looks like something different.

Any help much appreciated.