Thanks for posting. And good for you for creating a backup before attempting any big modification!
You say that this is your defined region - so I assume we are NOT talking about the ABA EURASIA REGION that comes already defined in BD - right?
If this is your location that you created, updating BD should have no effect on it at all. It may have an effect on ancestors or descendants that come pre-defined in BD, but not on a user-defined location. So, I am curious as to whether I understand the problem here.
First, make sure you are running build 62 of v4.1 (v4.1.62). If not, upgrade with Help | Internet: Check for an Upgrade.
Let's start here John. Let me know if we are talking about your Eurasia location or the "ABA EURASIA REGION" already defined in BD.
Note: Wile in the Locations window, you can right-click on any location (even WORLD) and choose "Export Selected Location's Descendants". This will export your location hierarchy to a text file for easy examination. If you export WORLD, you can attach that file in your reply so I can have a look at your hierarchy.