What is wp 2.0.X reading options php file?

What is wp 2.0.X reading options php file?

I have proplem, if i do change wp-reading options my wp (how many archives you want show your blog page). Basic is 10, but if i change exap. 4 and push buttom i give error message:
“Forbidden
You don’t have permission to access /xx/wp-admin/options.php on this server.”

🙁 🙁

I experiment every setup (cmod 777, 755 and more) but nothig help 🙁 .

Can i change “by hand” this options some wp- php file?

And what is file and what i change inside file?

Best.Regards -Jukka-