Error when i try to change ads

[kloden1]

I did move my site from one server to an ather, but now i the error message when i try to manage new ads in admin panel:
Warning: fopen(header_ads.txt) [function.fopen (http://travianforums.com/nbs/function.fopen)]: failed to open stream: Permission denied in /home/forum/public_html/nbs/admin.php on line 1479

Warning: fwrite(): supplied argument is not a valid stream resource in /home/forum/public_html/nbs/admin.php on line 1480

Warning: fopen(footer_ads.txt) [function.fopen (http://travianforums.com/nbs/function.fopen)]: failed to open stream: Permission denied in /home/forum/public_html/nbs/admin.php on line 1482

Warning: fwrite(): supplied argument is not a valid stream resource in /home/forum/public_html/nbs/admin.php on line 1483

Warning: fopen(first_post_ads.txt) [function.fopen (http://travianforums.com/nbs/function.fopen)]: failed to open stream: Permission denied in /home/forum/public_html/nbs/admin.php on line 1485

Warning: fwrite(): supplied argument is not a valid stream resource in /home/forum/public_html/nbs/admin.php on line 1486

what is wrong?
function verify() { return confirm('Are you sure you want to perform this action?'); }

[Derek]

CHMOD nbs/header_ads.txt, footer_ads.txt, and first_post_ads.txt to 777

[marcovit]

admin says that some files are still 777 and they need to change to 644 but i did that :\