SureAI

Quest-Divide and conquer-Can't complete dialog with Milbert Foxhand to acquire the quest due to persistent crashes to desktop when Milbert finishes talking.

Do you have any Mod´s installed? If so, which ones?
Disable or better uninstall them and then check your game with Steam. Test it again.
If there aren't too many, you can deactivate them one at a time until you find the guilty one.

To find other bugs, please upload a savegame here so we can test it. As you know, we need the -.ess and .-skse files to do this.
Please put them in an archive, because the forum does not support -.skse. You can find it here: ...\Documents\My Games\Enderal\Saves.
(if possible, no auto- or quicksaves, but saved manually)

PS:
Your error message was already there once, where mods was the problem.

Thanks for your help. I'll try your recomendations. Attached is the archive with a manual save.