What does this mean (A SMART error of hard disk)?

["Wang Xu" <gnawux@gmail.com>]

Hi list,

The following message was reported by smartd daemon several times,
it seems to be a hard disk error, but does this mean I should purchase
a new disk as soon as possible?

I checked the log file but got nothing.

The message:

*********************************************************
This email was generated by the smartd daemon running on:

  host name: inspiration
 DNS domain: localdomain
 NIS domain: (none)

The following warning/error was logged by the smartd daemon:

Device: /dev/hda, 1 Currently unreadable (pending) sectors

For details see host's SYSLOG (default: /var/log/messages).

You can also use the smartctl utility for further investigation.
No additional email messages about this problem will be sent.

*********************************************************

Thank you!

--
Wang Xu