'Some Contents Unreadable" error still exists after checking HDD

[Rajev Mhasawade]

Hi,
I did use shutdown now -Fr command and it checked filesystem after
reboot without detecting any errors and stating all drives are
'non-contagious'.Yet when i try to find out space used by each
drive(via right click),information displayed there does not match with
that of df -h.And the error (some contents cannot be read) is still
there.
What does this mean,is my HDD problematic?What should i do?Plz help!
Thanks in advance.
Rajev