[Tue Oct 30 20:09:00 2012] [error] [client 98.165.168.58] File does not exist: /home/persianw/public_html/favicon.ico
all same as this.

The favicon would have nothing to do with this issue.

Can you leave your site with plugins disabled and with the default style and then supply us with a username/password of a user that has the problem so we can view it using firebug and see what the issue is.

I turned of everything and I put that line back to CONFIG ,

Website
http://persian-wgamers.com/forums/forum.php

User
test1

pass
123456789
-----------------------------------------------------------
original style
Plugins

Digital Point Thread Avatars
Force Users to Read a Thread
Post Thank You Hack
Showroster Mod
Usergroup Legend on Forumhome
vBExperience
vBH - Add new tabs 1.2
VSa - ChatBox
VSa - PayPal Donate
VSa - Visitors in Last X Hours

the new tabs plugins has been updated by myself link in my sig

--------------- Added [DATE]1351710895[/DATE] at [TIME]1351710895[/TIME] ---------------

your problem might be all users have to fill in Image Verification before they post and your editor needs set to Enhanced Interface - Full WYSIWYG Editing for all users old and new

Why do you make registered users use image verification in order to post? Are you sure they are entering the correct letters/numbers and that that is not the problem?

I did that because of spam ,
Im not sure about one thing (activity Code)
But Why when I change it to other groups it works ?

Because you probably have the permissions correct for other groups OR the other groups don't have to enter the image verification code and so things are fine for them.