404 Page Not Found --> announce

[eluser]naiyumie natsume[/eluser]
Hi

I'm CodeIgniter newbie, I Like a CodeIgniter
programming in my works with I'am detection error messages.

Code:

system\logs\log-2011-02-09.php:
    "404 Page Not Found --> announce"
    ERROR - 2011-02-09 17:34:40 --> 404 Page Not Found --> announce

application not problem. but it makes me my feeling awful.
what is this error message?

teaching me please.