OctoberCMS Error In Frontend - Frontend Is Not Accessible Firing Error "Default Value For Parameters With A Class Type Hint Can Only Be NULL"

all I am new to OctoberCMS, i have installed already built project into my Ubuntu 16.04 system with PHP5.6 and apache2. I have successfully setup and run project backend after very hard trying. but problem is when i open any front-end URL then this error occurs:

Default value for parameters with a class type hint can only be NULL
/home/vasim/jannat/code/octoberdev2/plugins/look/casefiles/classes/ActivityLogger.php line 59

error screenshot

I have search it on Google and can not finding anything helpful and i have also find out that it is a rainlab plug-in error, I have uninstall and reinstall that plug-in but that also not worked. so, please can anyone help me with this error?

Any help will be appreciated.



It seems an error from a plugin called look/casefiles. If it's not your own plugin try to remove it and the application should works well.