Hey Guys. I run IPS 4.3.6 and would install the following Plugin 

After the Installation an Error was Shown

Error: Call to undefined method IPS\Session\Front::log() (0)
#0 /config/www/board/system/Node/Controller.php(717): IPS\Node\_Controller->logToggleAndRedirect(Object(IPS\Plugin))
#1 /config/www/board/applications/core/modules/admin/applications/plugins.php(132): IPS\Node\_Controller->enableToggle()
#2 /config/www/board/system/Dispatcher/Controller.php(85): IPS\core\modules\admin\applications\_plugins->enableToggle()
#3 /config/www/board/system/Node/Controller.php(62): IPS\Dispatcher\_Controller->execute()
#4 /config/www/board/applications/core/modules/admin/applications/plugins.php(38): IPS\Node\_Controller->execute()
#5 /config/www/board/system/Dispatcher/Dispatcher.php(146): IPS\core\modules\admin\applications\_plugins->execute()
#6 /config/www/board/admin/index.php(25): IPS\_Dispatcher->run()
#7 {main}

and Backtrace 

#0 /config/www/board/init.php(537): IPS\_Log::log('Error: Call to ...', 'uncaught_except...')
#1 [internal function]: IPS\IPS::exceptionHandler(Object(Error))
#2 {main}

now, if an want to save changes in the ACP .. the Error always appears. 

If i want to uninstall it:

Error: Call to undefined method IPS\Session\Front::log() (0)
#0 /config/www/board/system/Dispatcher/Controller.php(85): IPS\Node\_Controller->delete()
#1 /config/www/board/system/Node/Controller.php(62): IPS\Dispatcher\_Controller->execute()
#2 /config/www/board/applications/core/modules/admin/applications/plugins.php(38): IPS\Node\_Controller->execute()
#3 /config/www/board/system/Dispatcher/Dispatcher.php(146): IPS\core\modules\admin\applications\_plugins->execute()
#4 /config/www/board/admin/index.php(25): IPS\_Dispatcher->run()
#5 {main}

and Backtrace

#0 /config/www/board/init.php(537): IPS\_Log::log('Error: Call to ...', 'uncaught_except...')
#1 [internal function]: IPS\IPS::exceptionHandler(Object(Error))
#2 {main}

Can anyone Help me?

I can't reproduce. Works fine to me in localhost and live board:

This plugins is a simple button addition on a template. Nothing else.

Is this happening only with this plugin?

Something strange is happening on your board, not sure why, but your ACP is obviously using a Front Session instance.
 

Error: Call to undefined method IPS\Session\Front::log() (0)

okay that's really weird. I have now restored a snapshot of the vm. I have now reinstalled and there was no mistake. Very misterious.

Nevertheless, thanks for your quick reply 🙂