Problem importing blog with upgrade app (Perch 1 to 2 website upgrade)

Doing a website upgrade from perch 1 to 2 using upgrader app and I'm wondering if I'm having a similar issue as posted here

I'm getting a slightly different error when I run the upgrade app blog import:

PHP Fatal error:  Call to a member function setSlug() on a non-object in /Applications/MAMP/htdocs/website-name/cms/core/apps/categories/PerchCategories_Category.class.php on line 50

I wondered if I should try upgrading to an older version of the blog app first, as suggested in the previous post but the link is dead.

Appreciate support for this is about to die out but any help would be great.

Thanks.