If you saved after giving her the branch but before the summoning, then there is a way to get it to work. If you saved after she died, you can get her back as a merchant, but can not talk to her about any quests, etc.

Fix for giving Corinna a fake Talking Tree branch


If you have not done so already, installing the patch will add a second quicksave slot (by default, you can increase that number), and it wouldn't hurt to save under a unique name before completing quests, exploring new areas, etc. If you have a re-release version of DD it may already be updated to the latest 1.0034A version, as shown in the bottom right corner of the main menu.

Early Starter Tips (NON-Spoiler Version)