Question Can not Access Forum Categories and Posts

Hello everyone, I just installed Kunena 1.6.1 on my Joomla 1.5.21 site. Installation is OK and I just create a category section.
All links, like Rules, Profile, New Topic, are OK but when I try to access any of the post or forum section, an error occurres.
You can see my forum here Evcil Forum
And here is a post sample which is not accessed...
What is the problem? Thanks...

Database collation check: The collation of your table fields are correct

Legacy mode: Disabled | Joomla! SEF: Enabled | Joomla! SEF rewrite: Enabled | FTP layer: Disabled |

This message contains confidential information

htaccess: Exists | PHP environment: Max execution time: 30 seconds | Max execution memory: 32M | Max file upload: 2M

Joomla default template details : ja_social | author: JoomlArt.com | version: 1.2.0 | creationdate: 14/09/10

Kunena version detailled: Installed version: 1.6.1 | Build: 3858 | Version name: Timu | Kunena detailled configuration:

Warning: Spoiler!

[th]Kunena config settings:[/th]

board_title	Kunena
board_offline	0
board_ofset	0.00
offline_message	<h2>The Forum is currently offline for maintenance.</h2> <div>Check back soon!</div>
enablerss	1
enablepdf	1
threads_per_page	20
messages_per_page	6
messages_per_page_search	15
showhistory	1
historylimit	6
shownew	1
jmambot	0
disemoticons	0
template	default
showannouncement	1
avataroncat	0
catimagepath	category_images/
showchildcaticon	1
annmodid	62
rtewidth	450
rteheight	300
enableforumjump	1
reportmsg	1
username	1
askemail	0
showemail	0
showuserstats	1
showkarma	1
useredit	1
useredittime	0
useredittimegrace	600
editmarkup	1
allowsubscriptions	1
subscriptionschecked	1
allowfavorites	1
maxsubject	50
maxsig	300
regonly	0
changename	0
pubwrite	0
floodprotection	0
mailmod	0
mailadmin	0
captcha	0
mailfull	1
allowavatar	1
allowavatarupload	1
allowavatargallery	1
avatarquality	65
avatarsize	2048
allowimageupload	0
allowimageregupload	1
imageheight	800
imagewidth	800
imagesize	150
allowfileupload	0
allowfileregupload	1
filetypes	txt,rtf,pdf,zip,tar.gz,tgz,tar.bz2
filesize	120
showranking	1
rankimages	1
avatar_src	fb
fb_profile	fb
pm_component	no
userlist_rows	30
userlist_online	1
userlist_avatar	1
userlist_name	1
userlist_username	1
userlist_posts	1
userlist_karma	1
userlist_email	0
userlist_usertype	0
userlist_joindate	1
userlist_lastvisitdate	1
userlist_userhits	1
latestcategory	0
showstats	1
showwhoisonline	1
showgenstats	1
showpopuserstats	1
popusercount	5
showpopsubjectstats	1
popsubjectcount	5
usernamechange	0
rules_infb	1
rules_cid	1
help_infb	1
help_cid	1
showspoilertag	1
showvideotag	1
showebaytag	1
trimlongurls	1
trimlongurlsfront	40
trimlongurlsback	20
autoembedyoutube	1
autoembedebay	1
ebaylanguagecode	en-us
fbsessiontimeout	1800
highlightcode	0
rss_type	topic
rss_timelimit	month
rss_limit	100
rss_included_categories
rss_excluded_categories
rss_specification	rss2.0
rss_allow_html	1
rss_author_format	name
rss_author_in_title	1
rss_word_count	0
rss_old_titles	1
rss_cache	900
fbdefaultpage	recent
default_sort	asc
alphauserpointsnumchars	0
sef	1
sefcats	1
sefutf8	1
showimgforguest	1
showfileforguest	1
pollnboptions	4
pollallowvoteone	1
pollenabled	1
poppollscount	5
showpoppollstats	1
polltimebtvotes	00:15:00
pollnbvotesbyuser	100
pollresultsuserslist	1
maxpersotext	50
ordering_system	mesid
post_dateformat	ago
post_dateformat_hover	datetime
hide_ip	1
js_actstr_integration	0
imagetypes	jpg,jpeg,gif,png
checkmimetypes	1
imagemimetypes	image/jpeg,image/jpg,image/gif,image/png
imagequality	50
thumbheight	32
thumbwidth	32
hideuserprofileinfo	put_empty
integration_access	auto
integration_login	auto
integration_avatar	auto
integration_profile	auto
integration_private	auto
integration_activity	auto
boxghostmessage	0
userdeletetmessage	0
latestcategory_in	1
topicicons	1
onlineusers	1
debug	0
catsautosubscribed	0
showbannedreason	0
version_check	1
showthankyou	1
showpopthankyoustats	1
popthankscount	5
mod_see_deleted	0
bbcode_img_secure	text
listcat_show_moderators	1
lightbox	1
activity_limit	0

Third-party components: AlphaUserPoints: Disabled or not installed | CommunityBuilder: Disabled or not installed | Jomsocial: Disabled or not installed | UddeIm: Disabled or not installed

Plugins: System - Mootools12: Disabled | System - Mootools Upgrade: Enabled | JFirePHP: Disabled or not installed | Kunena Discuss: Disabled or not installed | Kunena Search: Disabled or not installed | My Kunena Forum Menu: Disabled or not installed | My Kunena Forum Posts: Disabled or not installed

Modules: Kunena Latest: Disabled or not installed | Kunena Stats: Disabled or not installed | Kunena Login: Disabled or not installed

This is very important for me to solve it. I am looking forward to see your solutions.
Thanks...

This is a similar problem to My Forum is having problems loading and I'm wondering if there isn't a common cause for what is causing these redirection "loops".

So I'll ask the same questions here as I did in the other topic:

Are you using your own, customised .htaccess file?

Are you using a third-party SEO product?

Yes I searched forum before I just posted and read that topic. But I have no 3. party SEF-SEO extension.
I don't have a custom .htaccess but I installed the template as quickinstallation. After installation, there was 2 htaccess files. One of them whith .txt extension and other one is .httaccess
So I just deleted txt one.

I just deleted my whole installation and install Joomla again and problem is OK.

when I activate the Search Engine Friendly URLs on the "Site / Global Configuration" and I try to enter any category on the forum I get an error (This webpage has a redirect loop.) every other page is working except the kunena forum url's...

HELP! :S