Cant upload logo

Hi, recently i install ojs v3.1.1.4 in server. the problem is when i upload logo in journal, setting->website->logo. it did not upload. i had check the error log, and did some research about it. they say the error does not effect the operation. i dont know where can i find a way to solve this. if someone had the same problem with me and solve, please guide me how to do it. Thank you.

PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with 
LazyLoadPlugin::getEnabled($contextId = NULL) in E:\Inetpub\vhosts\\httpdocs\ojs\
lib\pkp\plugins\generic\usageEvent\ on line 0 php_error

edit: since this problem is related to web hosting, i just change the logo manually from the source code.