Error page problem

afther instal backlight 3 i start to design . click on button show in browster.

I get an error page

also when i open it with my domain name it give no link to the page .

search of course a solution or a reason .maybe the rights from the root ore map ?

Thanks bob

not much to go on.
Did you upload the index.php and .htaccess files found in the root of the unzipped Backlight Installer folder to the root of the site?
check that the site url in Settings is correct.
can you also include a link to your site?