let me make one thing specific. if you have 'properly' installed unrar then you just have to click on it and click extract. no need of terminal even.
i use ubuntu but i use fedora more.
i dont think 'sudo apt-get unrar' will install unrar.
in fedora, i had to do some googling to get it installed. so check if you can open any other .rar file, probably problem is with your files.
second, you said its part01.rar,part02.rar etc... rt?. that can mean something. maybe you are trying to unrar the wrong file. its only a guess. try to unrar the main file(if any), it wont be having 'part (no)' before .rar.
maybe rwrk28201-52000.rar will be the main file in your case. extract it and it will extract all rest along with it.
be sure. unrar does works on .rar if used right.
let us know about how it went.