Wenn ich im notification_center eine Sprache editieren möchte, steht im Pop-Up folgende Fehlermeldung und sonst nichts:

Code:
Fatal error: require_once(): Failed opening required '/var/www/kunden/webs/kunde/kunde-domain.de/typo3/sysext/cms/tslib/class.tslib_eidtools.php' (include_path='/var/www/kunden/webs/kunde/kunde-domain.de/typo3/contrib/pear/:.:/usr/share/php/:/usr/share/php5/') in /var/www/kunden/webs/kunde/kunde-domain.de/typo3conf/ext/ws_404/class.user_pageNotFound.php on line 232
Code:
http://kunde-domain.de/contao/main.php?do=nc_notifications&table=tl_nc_language&field=languages&id=1&popup=1&rt=XXX&dcawizard=tl_nc_language%3A1&act=edit&id=1
Insbesondere, dass da typo3 im Pfad steht verwundert mich.

Der Hoster steht auch vor einem Rätsel. Hat hier jemand einen dezenten Hinweis, wo ich suchen muss?

System:

Contao 3.5.28
PHP: 5.6.31, 7.0.22, 7.1.8 durchprobiert (alle CGI)

Code:
{
    "name": "local/website",
    "description": "A local website project",
    "type": "project",
    "license": "proprietary",
    "require": {
        "bugbuster/easyupdate3": ">=3.5.0.0,<3.6-dev",
        "comolo/contao-supertheme": "2.3.1.0",
        "contao-community-alliance/composer-client": "~0.14",
        "contao-legacy/frontend_editor": ">=2.3.0.9003,<2.4-dev",
        "hofff/contao-horizontalrule": ">=3.1.0.0,<3.2-dev",
        "jrgregory/m17-sticky-backend-footer": ">=2.0.6.0,<2.1-dev",
        "metamodels/attribute_alias": ">=2.0.0.0,<2.1-dev",
        "metamodels/attribute_checkbox": ">=2.0.0.0,<2.1-dev",
        "metamodels/attribute_combinedvalues": ">=2.0.0.0,<2.1-dev",
        "metamodels/attribute_file": "dev-hotfix/order-field",
        "metamodels/attribute_longtext": ">=2.0.0.0,<2.1-dev",
        "metamodels/attribute_select": ">=2.0.0.0,<2.1-dev",
        "metamodels/attribute_tags": ">=2.0.0.0,<2.1-dev",
        "metamodels/attribute_text": ">=2.0.0.0,<2.1-dev",
        "metamodels/attribute_timestamp": ">=2.0.0.0,<2.1-dev",
        "metamodels/attribute_url": ">=2.0.0.0,<2.1-dev",
        "metamodels/core": ">=2.0.0.0-alpha14,<2.1-dev@alpha",
        "metamodels/filter_checkbox": ">=2.0.1.0,<2.1-dev",
        "metamodels/filter_select": ">=2.0.0.0,<2.1-dev",
        "metamodels/filter_text": ">=2.0.1.0,<2.1-dev",
        "psi/boxes4ward": ">=2.0.5.0,<2.1-dev",
        "psi/redirect4ward": ">=2.1.1.0,<2.2-dev",
        "terminal42/contao-pageimage": ">=3.3.0.0,<3.4-dev",
        "terminal42/notification_center": ">=1.4.1.0,<1.5-dev"
    },
    "prefer-stable": true,
    "minimum-stability": "dev",
    "config": {
        "preferred-install": "dist",
        "cache-dir": "cache",
        "component-dir": "../assets/components"
    },
    "repositories": [
        {
            "type": "composer",
            "url": "https://legacy-packages-via.contao-community-alliance.org/"
        },
        {
            "type": "composer",
            "url": "https://legacy-packages-via.contao-community-alliance.org"
        },
        {
            "type": "artifact",
            "url": "packages"
        }
    ],
    "extra": {
        "contao": {
            "migrated": "done",
            "version-locks": {
                "comolo/contao-supertheme": ">=2.3.1.0,<2.4-dev"
            }
        }
    }
}