Roberto,
thanks for all the translations!
Concerning the error message you are getting Jarkko is correct in his comment. Unfortunately there is no web interface for editing these parameters yet.
I will commit the catalog files later this week (keep reminding me if I forget...).
Concerning syncing different catalog files for the same locale and package we have no support for that and it would have to be done manually. If somebody starts translating portugese on the translation server in parallel to your efforts you have a bit of a problem, at the very least you would probably want to coordinate closely with them.
