For qute a whiile i thought to propose/post this on here.
I think We should include Error pages in the phpbb software, that use the current style (header/footer) of the forum.
I use the following mod on my board, even if its a few versions behind.
http://www.phpbb.com/customise/db/mod/th23_error_pages/
I had in mind to write my own one by using the default .shtml server files and trying to include the header and footer pages (dont remember how.. probably using iframe or including the html files .. whatever)


