SMART reallocates clusters as needed when some have failed. The percent that have failed have exceeded the limit SMART can tolerate. While you could turn off SMART and get several more months out of the drive, (or none at all), it is a good sign things are going bad.
around november of last year I had a drive that worked for about a week but then started failing the SMART test, a day later I couldn't open some of my media files on that drive because they were corrupt. RMA'd it with a note about how it failed the SMART test and they sent me a new one without a problem.
Bad just happens. every product has its bad supplies, and you probably were unlucky enough to get the bad one. only HD's that I have had continuous problems with were the Maxtors. avoid em like the plague! otherwise RMA it and you should have no problem.
odd, might have been a glitch. here, run this and see if anything is out of tolerance. it checks the data directly from smart and should tell you what, if anything has been exceeded by smart. might have just been a glitch... http://www.passmark.com/products/diskcheckup.htm