Smart Short Test Results : Fail - 0x77

Hi -

About a week ago, or so, I started noticing a whinning type noise coming from my directv DVR during playback.  Around the same time I also noticed picture freezing and audio going out during playback.  The symptoms became more noticable and increased in frequency the last few days.  And then yesterday I noticed it would happen with regular tv as well. 

Based on other threads I did a reboot/reset and ran the advanced Hard Drive utilities and received the Smart Short Test Result Fail -0x77

So, my question is:

1 - What happened here? I have had this dvr for almost 2 years with no problems outside of storms and cloudy days requiring a reset to continue watching television.  I never expected DVRs to just die!  Don't ask me why, I just thought they would live on forever and ever....

2 - Is the suggestion that I call Directtv and complain about my box not responding, which it is not, and request a replacement?  If so, would I be expected to pay for this?

3 - Lastly, I"m a curious bee, What does that test actually test in the hard drive?  Is it similiar to a chkdisk / defrag command on a computers hard drive?

Thanks, this forum is so very helpful.....