[TYPO3-english] Translation handling and backend language

[Sergio Catalá Gil]

Same for me. 

My tables and fields are updated (using COMPARE section on Install tool)
and my caches are cleared. 

I still can't change my BE language despite I've got the option to do it
in the dropbox list (User settings). 

I've tested a new and clean installation of TYPO 4.3.0 and everything is
OK, I can change my language. So I think it's something about
upgrading.