Hi Bartek,
Thank you for the html source code, we got it today.
I have tried in several environment using the same tab type names and settings that we can see in the html file, that works perfectly, so we have no idea what is the exact problem.
We have found several posts about similar WordPress metadata saving problem, where the reason was a plugin collusion.
We have the following possibilities:
-Try to deactivate other plugins, to find out if there are plugin collusion or not (it would be great to found the problem this way).
-Give as access to your system, thus we can see the problem in greater detail.
Please let us know what is your choice.
Peter
(There is one more thread about a very similar problem:
http://webshoplogic.com/forums/topic/cant-get-any-version-to-work-reliably/)