Hi Michael, thank you your response.
You right! seens some kind of conflict.
I disabled the download plugin and I had the browse button working. Then I turned it on again and split the upload and download in two different pages and it also worked just fine:
Upload
http://hieletronico.com.br/index.php/arquivos
Download
http://hieletronico.com.br/index.php/arquivos-2
Any hint?
thank you so much for the assistance.