my $file = "//Administrator/Web Sites/Learning/myweek_$no.html";

    if ($file =~ /^([-\@\w._:\/]+)$/) {
        $file = $1;              # $data now untainted
    } else {
           print "Please report this error to the admin.  Thanks";  exit; 
    }

open OUTPUT, ">$file.html";
print OUTPUT $template->output;
close OUTPUT;