Tanks, Ivan. Lets share the solution:
I was using Joomla 1.7.2, and after upgrading to 1.7.3, the issue cames up.
My language pack is pt-BR_joomla_lang_full.1.7.2v1.zip.
Check your language directory, and find this file:
language\en-GB\en-GB.com_content.ini if English, or:
language\pt-BR\pt-BR.com_content.ini if Portuguese-BR, or your equivalent language file.
Search this two definitions, like I found in en-GB.content.ini language:
COM_CONTENT_PUBLISHED_DATE="Published Date"
COM_CONTENT_PUBLISHED_DATE_ON="Published on %s"
If you have the same problem I had, probably in your language content.ini file you have just one definition: Include the second line definition as above to solve the issue.
The next oficial language pack version probably will solve this problem.
