Good morning all

I have a full working system on our pre-production environment which has:

1. a number of content types
2. a number of site collection reusable workflow templates (using the above content types)
3. a number of associations in site content types > workflow settings

I have come to release these manually to production and have got as far as:

1. creating all the content types
2. creating and publishing all of the site collection reusable workflow templates (using the above content types)

but when I go to:

site settings > site content types > {choose content type} > workflow settings > add workflow

I get an error - the correlation returns this:

System.ArgumentException: An item with the same key has already been added. 

has anyone come across this issue before?  As I said it is absolutely fine on my other environment and I have no idea where to start looking for the issue.