Rapidleech unrar problem

I cant unrar my files with Rapidleech it was getting permission denied error then i have give CHMOD 777 to unrar file in /rar/ directory then its starts to give unrar not found error ?

" /home/thorn/rapidleech/rar/unrar: not found "

Is not anyone got this problem?

You probably need to edit some config and specify a path to some unrar command…have you googled for an answer?

Yes i have searched at google but answers not solve my problem coz all answers are too old. And rapidleech is not updated software. rar and unrar is working at my seedbox but at PHP side getting error. I think i need true rar and unrar files but i could not find. My os is ubuntu 16.04 x64.