HI:

Where can I find the phrase, that is visualizes on the Register Use Page:

"*Note: Membership to this portal is Private. Once your account information has been submitted, the portal Administrator will be notified and your application will be subjected to a screening procedure. If your application is authorized, you will receive notification of your access to the portal environment."

in order to translate it to portuguese language

All the best

Rui Macdonald

Hello Rui,

The text you are searching for is stored in the following locations:    

DNN up to v.4.5.5,    Directory\File: ~\admin\Users\App_LocalResources\ManageUsers.ascx.yy-XX.resx
DNN v.4.6.0 and up,    Directory\File: ~\App_GlobalResources\SharedResources.yy-XX.resx

Note 1: yy-XX is the culture code (i.e., en-AU, es-ES, etc.), for US English yy-XX does not exist.
Note 2: You should change this values using DNN's Language Editor. It gives you the possibility to make "permanent" changes or "overwritable" ones. For further recommendations on what I mean by "permanent" changes, please check my post at: http://www.dnnenglish.com/Default.aspx?tabid=72&EntryID=2

Saludos!