的Joomla! 3.4.5无法输入后端扩展管理器错误500

I can't enter my joomla! 3.4.5 back-end's Extension-Manager anymore!
I'm receiving this error (with debug mode info):

An error has occurred.
        500 View class not found [class, file]: installerViewinstall, /var/www/vhosts/einserpasch.com/httpdocs/administrator/components/com_installer/views/install/view.html.php

Call stack  
#       Function                                    Location    
1       JApplicationCms->execute()                  /var/www/vhosts/einserpasch.com/httpdocs/administrator/index.php:47 
2       JApplicationAdministrator->doExecute()      /var/www/vhosts/einserpasch.com/httpdocs/libraries/cms/application/cms.php:252  
3       JApplicationAdministrator->dispatch()       /var/www/vhosts/einserpasch.com/httpdocs/libraries/cms/application/administrator.php:152    
4       JComponentHelper::renderComponent()         /var/www/vhosts/einserpasch.com/httpdocs/libraries/cms/application/administrator.php:98 
5       JComponentHelper::executeComponent()        /var/www/vhosts/einserpasch.com/httpdocs/libraries/cms/component/helper.php:372 
6       require_once()                              /var/www/vhosts/einserpasch.com/httpdocs/libraries/cms/component/helper.php:392 
7       JControllerLegacy->execute()                /var/www/vhosts/einserpasch.com/httpdocs/administrator/components/com_installer/installer.php:19    
8       InstallerController->display()              /var/www/vhosts/einserpasch.com/httpdocs/libraries/legacy/controller/legacy.php:728 
9       JControllerLegacy->getView()                /var/www/vhosts/einserpasch.com/httpdocs/administrator/components/com_installer/controller.php:42   
10      JControllerLegacy->createView()             /var/www/vhosts/einserpasch.com/httpdocs/libraries/legacy/controller/legacy.php:863</code>

Before that I had some problems installing a plugin, so I changed my /httpdocs/libraries/joomla/filesystem/folder.php in line 227 from

$obd = ini_get('open_basedir');

to

//$obd = ini_get('open_basedir');  

After that I could install my plugin.
I don't know if that has something to do with my extension manager problems.
but I undid this edit in folder.php and it didn't fix the problem.

Problem solved by myself:
The view.html.php file was just empty for some reason.
I filled it with the content from the same file in the same directory of the joomla 3.4.5 installation package.