See my previous comment

Ok Dear friend I just installed OSSN v4.1 and log out error persists : "The action you Requested is invalid "...I did right click on log out option and showed me this link : http://localhost/ossn/action/admin/logout?ossn_ts=1459960978&;ossn_token=2df169919f00a54fc6e40e4008224719
Please help me. Sorry for inconvinences. Thanks

I am sorry for my last wrong comment, we can not reproduce issue without enough knowledge ,
Did you tried to install on some other local computer?

Dear friend, I am trying to install OSSN v4.1 and I get the error during installation "MOD_REWRITE IS REQUERID" , which is wrong , because phpinfo ( ) show me that if it is.

Try to enable display errors in administrator basic settings , and try to logout again and see if there is something in error_log.

Yes, there is the .htaccess file in root of ossn files.

on xampp the mod_rewrite is enabled by defafult, make sure there is .htaccess file in root of ossn files

Dear friend, sorry for the wrong way to locate the screenshot, but I am using xampp 1.8.2, and phpinfo() give me the following configuration, where you can see that MOD_REWRITE is active. Thanks for advance.

Configuration
apache2handler
Apache Version Apache/2.4.17 (Win32) OpenSSL/1.0.2d PHP/5.5.30
Apache API Version 20120211
Server Administrator postmaster@localhost
Hostname:Port localhost:80
Max Requests Per Child: 0 - Keep Alive: on - Max Per Connection: 100
Timeouts Connection: 300 - Keep-Alive: 5
Virtual Server No
Server Root C:/xampp/apache
Loaded Modules core modwin32 mpmwinnt httpcore modso modaccesscompat modactions modalias modallowmethods modasis modauthbasic modauthncore modauthnfile modauthzcore modauthzgroupfile modauthzhost modauthzuser modautoindex modcgi moddavlock moddir modenv modfilter modheaders modinclude modinfo modisapi modlogconfig modcachedisk modmime modnegotiation modproxy modproxyajp mod_rewrite mod_setenvif mod_socache_shmcb mod_ssl mod_status mod_version mod_php5

The screenshot you provided is avaialble on to you , its localhost , we can't access the screenshot.

If you are using wampp see : http://forum.wampserver.com/read.php?2,30758,30767

First of all thank you for your attention. I don't have domain.com yet but I'm doing the tests locally on my PC on Windows 7 and Apache Server localhost. I just installed OSSN v 4.1 , and validation page tells me I must have activated the MOD_REWRITE, however I have already activated as you can see in the screen shot attached here. Please tell me that 's what this probably doing it wrong.