win2000 server mail() problem

[Anon]

Hi,
First of all, I can't write English well. Sorry.
I use wind2000 server, apache web server and php 4.1.1.
Problem is mail messages are not delivered.
I use mail(). Source codes are following.

if(mail($to, $topic, $content, $headers))
{
echo "messages were delivered successfully<br>";
}
else
{
echo "Could not deliver your messages<br>";
}

The error messages are "Warning: Server Error in c:\localhost\sajuclub\mailing\mail_test.php on line 34"

Line 34 is if(mail($to, $topic....

On php.ini
[mail function]
; For Win32 only.
SMTP = localhost

; For Win32 only.
sendmail_from = webmaster@sajuclub.co.kr

And SMTP is performing.

I don't know what can I solve this problem.
Let me know method.
Thank you.