lame question regarding unpacking game

[yongpadawan1]

i downloaded a ps2 dvd rip game in rars to try out burning with my new pioneer A03 writer - silenthill 2 - when i try to unrar it i get a disc is full warning-im putting it on a thirty gig hard drive so space isnt the problem. do I need special software to unpack the game other than winrar ? Thanks for your help guys