Error occured...

i use windows 7 and i installed ejabberd server
but if i start ejabberd server.
after a while with 'starting ejabberd...',
then in web page, Error occured...
Please check your configuration and your installation.
if you are an advanced user, you can check the logs to check what is going wrong.
..
.
in ejabberd.log file
=ERROR REPORT==== 2010-05-17 21:34:00 ===
C(<0.189.0>:ejabberd_captcha:331) : The option captcha_cmd is not configured, but some module wants to use the CAPTCHA feature.

=INFO REPORT==== 2010-05-17 21:34:00 ===
I(<0.36.0>:ejabberd_app:199) : Adding machine's DNS IPs to Erlang system:
[]

=INFO REPORT==== 2010-05-17 21:34:03 ===
I(<0.36.0>:ejabberd_app:69) : ejabberd 2.1.3 is started in the node ejabberd@localhost

=INFO REPORT==== 2010-05-17 21:34:12 ===
I(<0.36.0>:ejabberd_app:86) : ejabberd 2.1.3 is stopped in the node ejabberd@localhost

any advice?