WD5001AALS with Damaged Blocks, Do I have to RMA it?

My new WD Caviar Black WD5001AALS was very noisy for the first 10 seconds at first start up, with an error disk during first boot. After resetting the pc, everything continued normally and I proceeded with W7 installation with no problem but, not quite convinced by its first behaviour, I than decided to do some testing. I connected the hard drive as a second drive in my old XP system and I've tried DLG several times: it FAILS the QUICK TEST but it passes the EXTENDED test and the DLG's WRITE ZEROS utility.I’ve also tried  an other diagnostic tool HD Tune Pro 4.01 and this one says that the drive is “AT RISK” and the complete scan gave 40 errors with 1.6% “Damaged Blocks”HD Tune Pro: WDC WD5001AALS-00L3B2 Error ScanScanned data   : 465 GBDamaged Blocks : 1.6 %Elapsed Time   : 1:53:041  Error at 141524 MB (LBA 289841695)2  Error at 242283 MB (LBA 496197199)……………….………………..40  Error at 390017 MB (LBA 798756788) Do I have to RMA it?