Dear partners 
I am trying to add a New menu item in the main menu and there is an error 
Server Error
500 - Internal server error.
There is a problem with the resource you are looking for, and it cannot be displayed.
Please I need some help on this issue.

The link to our site is: event.kentromeletis.edu.gr

Thank you in advance ….

Hello Nektarios,

Make sure you update to Joomla! 3.3 and the latest version of K2 as well.

Chances are that since this a couple of months old, that other extensions might need updating as well.

Another thing you could do is enable error reporting to see the actual error and which extension is causing it.

joomla 3.3 and K2 v2.6.8 Krikor.

Krikor i use your contact form and i sent you username to see if you can :)

I haver bad news I am afraid.
It is related to your server setup. It is possible that J! 3.3 does not play all that well with IIS 7.5 .

I could not change the configuration of the site as well. I got 500 errors when I tried to open error reporting.

Finally IIS 7 is recommended for Joomla! sites.www.joomla.org/technical-requirements.html

what can i do Krikor

Sadly I am not experienced in Windows Servers.

I can give you some alternatives though.
a) Try if Joomla! 2.5 is working properly.
b) Search on Joomla! forums about IIS configuration if you are maintaining the server
c) Contact your hosting provider and let them know about that issue
d) Worst case scenario: Look for an alternate cheap Linux host just for that subdomain.

Some resources: www.joomlaworks.net/forum/forum-updates-other-resources/2572-recommended-shared-hosting-in-case-you-re-frustrated-with-your-current-one

docs.joomla.org/IIS

www.google.gr/search?num=30&es_sm=119&q=joomla+iis+7.5+500+menu&oq=joomla+iis+7.5+500+menu&gs_l=serp.3...29047.30176.0.30514.5.5.0.0.0.0.149.602.1j4.5.0....0...1c.1.42.serp..4.1.148.gGsR8limVEs

i have the same configuration on the main site (with newsworth).... and it's ok...
Krikor if I asked to change the server to linux the problem would be solved?

I am not really sure how to advise you on this.
PHP applications are best hosted in Linux/Unix systems, that's true. I cannot advise anything to that matter because I have no idea about your setup/ requirements.

Before migrating or making any choices ask your hosting provider to check the error_log and see if they have a solution for this error.