why does utorrent say i dont have enough hard disk space when i clearly do?

ok, so the question is obvious, i have never had a problem with it before today, i'm not really computer savvy so please keep it simple. i tried researching and came across something to do with "fat32" and changing this to "ntfs" or something like that. i have no clue what this is BUT the point to these formatting things i researched were that "fat32" doesn't allow file sizes larger than 4GB and i need to change to "ntfs" to , but i have downloaded files above 50GB to the same drive before, i haven't played with any settings or anything like that and the drive is working as good as ever. except for this one little error that utorrent reports. can someone please tell me if i should be concerned or if its a bug in utorrent or something. i'm not too worried atm unless one of you give me something to worry about lol. Also i'm just curious as to what the deal is here. Thanks in advance guys.