Upgrade error

Hi all, i'm trying to upgrade from v.4.4.1 to 6.00.207. I think i've done like in the manual.

when i click on Upgrade from the Admin panel i get this error:

Fatal error: main(): Failed opening required 'THEMEtheme.php' (include_path='.;c:\php\includes') in D:\Inetpub\webs\xxxxxxxxit\public\subheader.php on line 12

can someone tell me why is that?

there are only two things on wich i'm not sure:
- i uploaded the config on the server, then the manual says to delete the one on my hard disk...is it right?
- the file upgrade.php that i'm going to upload on the server is overwriting the already existing file, is it correct?

other question: where do i have to put files so that the link won't show for ex: .../public/news.php
but directly: .../news.php
i have a windows server

one last question, why if Fusion is at V.6.xx people that is in charge of it don't put up a complete package up to date so that we don't need to do every time upgrades?

thank you very much, i hope someone can help someway