Internal server error

[sebdar]

Hi,
I wonder if you will be able to help me.
I'm no longer able to log on to agent panel on my OTRS. Customer side is working casue I can log on my customers but not an agent.
After inserting username and password for agent I'm reciving error: "Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, root@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Here is today's log from /var/log/httpd/error.log
I'm running Centos with the latest OTRS.

"[Fri Apr 25 16:42:58 2014] -e: Use of uninitialized value in shmread at /opt/otrs//Kernel/System/Log.pm line 282.
[Fri Apr 25 16:42:58 2014] [error] [Fri Apr 25 16:42:58 2014] -e: Identifier removed at /opt/otrs//Kernel/System/Log.pm line 281.\n
[Mon Apr 28 09:47:18 2014] [notice] SELinux policy enabled; httpd running as context system_u:system_r:httpd_t:s0
[Mon Apr 28 09:47:18 2014] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Mon Apr 28 09:47:21 2014] [notice] Digest: generating secret for digest authentication ...
[Mon Apr 28 09:47:21 2014] [notice] Digest: done
[Mon Apr 28 09:47:22 2014] [notice] Apache/2.2.15 (Unix) DAV/2 PHP/5.3.3 mod_ssl/2.2.15 OpenSSL/1.0.0-fips mod_wsgi/3.2 Python/2.6.6 mod_perl/2.0.4 Perl/v5.10.1 configured -- resuming normal operations
[Mon Apr 28 09:51:01 2014] [error] mkdir /opt/otrs/var/tmp/CacheFileStorable/CacheInternalUser/5/f: Permission denied at /opt/otrs//Kernel/System/Cache/FileStorable.pm line 79\n
[Mon Apr 28 09:54:47 2014] [notice] caught SIGTERM, shutting down
[Mon Apr 28 09:55:35 2014] [notice] SELinux policy enabled; httpd running as context system_u:system_r:httpd_t:s0
[Mon Apr 28 09:55:35 2014] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Mon Apr 28 09:55:39 2014] [notice] Digest: generating secret for digest authentication ...
[Mon Apr 28 09:55:39 2014] [notice] Digest: done
[Mon Apr 28 09:55:39 2014] [notice] Apache/2.2.15 (Unix) DAV/2 PHP/5.3.3 mod_ssl/2.2.15 OpenSSL/1.0.0-fips mod_wsgi/3.2 Python/2.6.6 mod_perl/2.0.4 Perl/v5.10.1 configured -- resuming normal operations
[Mon Apr 28 09:57:52 2014] [notice] caught SIGTERM, shutting down
[Mon Apr 28 09:58:40 2014] [notice] SELinux policy enabled; httpd running as context system_u:system_r:httpd_t:s0
[Mon Apr 28 09:58:40 2014] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Mon Apr 28 09:58:43 2014] [notice] Digest: generating secret for digest authentication ...
[Mon Apr 28 09:58:43 2014] [notice] Digest: done
[Mon Apr 28 09:58:44 2014] [notice] Apache/2.2.15 (Unix) DAV/2 PHP/5.3.3 mod_ssl/2.2.15 OpenSSL/1.0.0-fips mod_wsgi/3.2 Python/2.6.6 mod_perl/2.0.4 Perl/v5.10.1 configured -- resuming normal operations
[Mon Apr 28 09:59:36 2014] [error] mkdir /opt/otrs/var/tmp/CacheFileStorable/CacheInternalUser/5/f: Permission denied at /opt/otrs//Kernel/System/Cache/FileStorable.pm line 79\n
[Mon Apr 28 10:05:09 2014] [error] mkdir /opt/otrs/var/tmp/CacheFileStorable/CacheInternalUser/5/f: Permission denied at /opt/otrs//Kernel/System/Cache/FileStorable.pm line 79\n
[Mon Apr 28 10:08:08 2014] [notice] SIGHUP received. Attempting to restart
httpd: apr_sockaddr_info_get() failed for SRVLSNC001.xx.local
httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName"

[crythias]

First disable selinux

[sebdar]

It worked, thank you!!!!!
I have no idea why it was enabled.