Hello i need help i have installed the new ver.3.18 and i want it in german language. How this can be done?Thx

If your WP install is German, Atahualpa 3.1.8 should automatically display in German too. The remaining English terms you might see can be adjusted via the Atahualpa Theme Options.

Does the Languagetranslation only affect the frontend?

Yes, only the front end is translated

I use the german Wordpress 2.7 on my server, but Atahualpa doesn't recognize the right language. Can i manually activate the German translation?

Only the hard coded text parts would appear in German. Some text, such as the post footers etc, can be configured freely via the theme options and would still be in English until you changed them through the Theme Options. If the "Leave a Reply" above the comment form is German then it's working.

The language does not need to be enabled. If your WP installation is in German, and there is a de_DE.mo file inside /wp-content/themes/atahualpa3/ then the theme should switch the language automatically.

Hello!
Reading here I could understand that some translations are to be done in Theme Options and OK, this is not so difficult. But the Theme comes with a POT file wich I translated, named it pt_PT for Portuguese and put the .mo file in the same directory. But I can't see if something was translated? Is this correct? If not, where shall I put the file then?
Regards