My apologies Steve, and thanks for Your patience, I' try all combination and Your suggestion have the same result, so, I suppose I've make an error (or "errors"), in the installation process. Find my steps:
1-after a download Unzip the installation package
2-edit the web.config to MsSQL access
3-with a ftp client (filezilla) i've open ftp.mysite.org
4-I make a new dir so: mysite.org\dnn
5-then I put with ftp client all file unzipped in new remote dir such: disk:\dnn\*.* --> ftp.mysite.org\dnn\*.*
6-after this I call the new dir with browser: http:\\www.mysite.org\dnn
7-the result is a described error page.
Thats all.
Thanks again.
Valerio