Any way to disable "in-house" plugin (wp-clan?)

Hi, is it possible to disable the default wp-clan. It was not look really nice on the admin cp( http://imgur.com/vhscEnL) and generate a lot of error on the website like all of these:

For your information, If I download, upload and activate the wp-clans plugin, it won’t enable cause you have it by default. Is it latest version?
Since I have 2 menus in the admin menu (left column) (http://imgur.com/GTsCwwM)

This error was on the matches page…(http://imgur.com/a/5iASM)
Notice: Undefined variable: alt in /home/xxxxxxx/public_html/example.com/wp-content/themes/blackfyre/addons/clan-wars/wp-clanwars.php on line 3593

On the header, I see: (http://imgur.com/QzaNr8x)
Notice: Undefined index: _checkbox_clan_user in /home/xxxxxxx/public_html/example.com/wp-content/themes/blackfyre/header.php on line 100
Notice: Undefined index: _checkbox_clan_user in /home/xxxxxxx/public_html/example.com/wp-content/themes/blackfyre/header.php on line 68

Under clan page, we see: Clan page, Members, Matches.
Matches tab was fucked: (http://imgur.com/6s1hvDV)
Notice: Undefined variable: challenge in /home/xxxxxxx/public_html/example.com/wp-content/themes/blackfyre/single-clan.php on line 260

Also for woocommerce (the shop tab on the main menu) I see: (http://imgur.com/pHVNMs1)
I have this error: Notice: woocommerce_get_page_id is deprecated since version 3.0! Use wc_get_page_id instead. in /home/xxxxxxx/public_html/example.com/wp-includes/functions.php on line 3831

On the admin CP, when I try to edit a page OR when I am on the users tab in admin cp, I get this error at the top: (http://imgur.com/JW2iVwX)
Notice: Undefined index: login in /home/xxxxxxx/public_html/example.com/wp-content/themes/blackfyre/functions.php on line 4166

On the simple clan page, I see:
Notice: WP_User->id was called with an argument that is deprecated since version 2.1.0! Use WP_User->ID instead. in /home/xxxxxxx/public_html/example.com/wp-includes/functions.php on line 4023

Another thing: when I click on a member to go on his profile, the latest news was not displayed correctly: http://imgur.com/gj3mnIq
It works on every other page, but not this one…

When I click on groups for a member, I have this on the header:
Warning: preg_match(): Unknown modifier ‘(‘ in /home/xxxxxxx/public_html/example.com/wp-includes/class-wp.php on line 232

Also in the blog right sidebar, I have TWO search form: (http://imgur.com/E2UoCmL)
How I can fix this? I check the sidebar file, but it was not used for all sidebars…

Also the templates for visualcomposer are not detected by visual composer. Where I can put them to allow it to detect them?

And is it possible to COMPLETLY disable the matches option? Since I don’t need it.

I am probably stupid to have all of these errors, but it is very iportant to me to fix them. If you can help me, it would be really amazing.

Thank you so much and have a nice day/night to you,
Maxime.

I think it’s good for the moment