Hi David,
This looks like a bug in the upgrade process.
What version are you trying to upgrade to?
Do you currently have newsletter subscribers?
It seems the problem is the post upgrade task for 2.3.2.0 calls the DBLetterSubscription.Create method, but the problem is the signature of that method changed in a later version to include this additional ipaddress field, but when this post build event runs it errors because that column is not added until a later script.
The reason I never encountered the error is because I upgraded after each version so this method had already run before the method signature changed for me and therefore no error occurred.
I can fix this going forward but I may have to create a custom page to help you fix the problem for existing newsletter subscribers. I recommend backup your mp_LetterSubscriber table as this table will get dropped and it will need to be restored to get the data correctly loaded into the newer table named mp_LetterSubscribe which is what this post build event was trying to do, but it will not run more than once since the 2.3.2.0 script already has run.
Sorry for the inconvenience but I will try to help you solve this. Backup your mp_LetterSubscriber table so you can get it back and then see if it can run the rest of the scripts by visiting setup again.
Best,
Joe