When using an add-in you can't use My.Settings. What I do is use a text file with a custom extension. I save and read this file as my own personal My.Settings file. I highly recommend comments in the subs and functions that you use to read and write to the text file so if you have to make changes to the text file a year from now it will be easier to do. Also, I would have a "CreateNewSettingsFile" sub ready to go in case the user moves or deletes the settings file from your specified location.
thanks for your reply.
I think that I will follow your advice, working with text files.