Pakkurti,
To expand on what Bogdan said, this is potentially a very dangerous operation. It has caused us to have to restore our dev environment.
From my experience, if you use OMA file transfers, it's VERY important to make sure you only make Extension Definition AND Value List Type changes in only one environment and transport them from there in a one-way direction.
You may be thinking, "this is bad practice-- we always go Dev -> QA -> Prod." But it can actually occur easily between a sandbox and dev. Seems like common sense at the time, make your experimental changes in sandbox so you don't trash up your dev system, then export them over to dev-- BUT if someone else makes changes in dev in the interim, this problem can occur.
The way SAP recommends is workbooks but it also has problems of it's own since it's entirely manual and easy to enter invalid values accidentally. Also version control of the workbooks is very important.
Hope this helps.
Mike