Important problem installing from 1.6.5 to 1.7

Hi guys I just downloaded the new version 1.7 Kunena .... and I was trying to install it on my current version to 1.6.5, I soo that generates this error when installing

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Now even if you did not install anything the problem and that if I put my site offline in FireBoard 1.5.6 no longer gives me this error:"

Errore del server
Si è verificato un errore nel sito web durante il recupero di www.noiceliaci.it/ . Potrebbe non essere disponibile per manutenzione o essere configurato in modo errato.
Ecco qualche suggerimento:
Ricarica questa pagina web più tardi.
Errore HTTP 500 (Internal Server Error): Si è verificata una condizione imprevista durante il tentativo del server di soddisfare la richiesta.

how do I do with 'The update?? My System - Upgrade Mootools Mootools version 1.2.4 and Joomla 1.5, so it's good?
Aspect of your response

Hello,

You have issue permissions on your sytem, you need to fix that and then re-try to install kunena.

dontorus wrote: Uploaded with ImageShack.us
Now even if you did not install anything the problem and that if I put my site offline in [strike]FireBoard[/strike] Kunena 1.5.6 no longer gives me this error:e

xillibit wrote: Hello,

You have issue permissions on your sytem, you need to fix that and then re-try to install kunena.

dontorus wrote: Uploaded with ImageShack.us
Now even if you did not install anything the problem and that if I put my site offline in [strike]kunena[/strike] Kunena 1.5.6 no longer gives me this error:e

I have the folder permissions problems?? In practice should enable the system folder or pemessi Kunena Do not Understand What should I do exactly

I'm sorry I wanted to specify the version of kunena 1.5.6, but that is not my version 1.6.5 is implemented there was a typo

ok now I installed 7.1 Kunena and discussion topics have remained just that any discussion I get this line, why?

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the site as you understand it in Italian is my mother tongue I just hope I'm writing the text was translated properly.
aspect of your news

I resolved I set the Debug Mode is yes..thanks again ... one last thing where I find the new templates to download kunena