Sorry for no asnwers but I was on vacation fro few days.

Reines: I do not have access to " .htaccess" or any other system files.

Rickard: thx for answer

What do you mean by "freash viewtopic.php"?
I have PunBB 1.2.10.

I tried to experiment with viewtopic.
I changed relative definition of root ("./") in the beginning of script to absolute ("/usr/home/......"). It gave no results.

However what is very interesting if I change viewtopic.php filename to any other eg. viewtop.php
and try to execute it like
http://punbb.org/forums/viewtop.php?id=<some existing ID>
it works perfectly.

Is it possible that on my host filename viewtopic.php is somehow reserved or blocked by system ?????

The only idea I've got to make it work is to change filename of viewtopic.php in all script's it is used in.

I have chmod'ed permissions of everything in the folder containing PunBB to 777 including the folder itself.

No matter if I want to view topic after changing it by Admin, user, or just view it as guest, and no matter what internet browser I use, I still get the following

"
Forbidden
You don't have permission to access /fireshow/pun/viewtopic.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/1.3.33 Server at vathelp.pl Port 80
"

My forum is at http://vathelp.pl/fireshow/pun/

Everything other works perfect - users can register and as Admin I can do anything except above.

Please help.