Make sure the translations are made correctly. Errors can happen if you miss a "," or can be due to encoding problems while ftp the files. As we dont have access to your code, the help anybody can you provide is limited.

You could also use a plugin to make the translation files for you. This will prevent making mistakes. For example the Translation Editor could help you with that.

http://community.elgg.org/pg/plugins/project/385116/developer/jeabakker/translation-editor

I´m using the 'translationbrowser' to deliver the translation to Brazilian Portuguese.  

I´ve made some modifications on it to work fine in a desktop XAMPP.

see: Elgg 1.8 / Elgg 1.7 - Brazilian Portuguese (pt-br) - traducao do Elgg para Portugues Brasileiro

thanks guys with the translation editor i resolve my problem.

but i've a question, when i click save elgg display a fatal error, it's normal ?
after this work perfectly

thanks :D 

That's not normal, what is the error?

this is the error:

Redirect not be released due to headers already being sent. Stopping the runningfor safety.