Mail problem

Hi, I am trying to send out an email to about 2500 users that are stored in a Mysql database. It doesn't quite work though, it will send them in bunches, then I will get a few of the error: Warning: Could not execute mail delivery program in /home/httpd/html/web/index.asp on line 194 Then it will work for a while then back to the errors. I know the email it is trying to send to are good. And it allways fails at different points anyway. Is the webserver trying to send email faster than sendmail can handle it? Should I be inserting a time delay before each mail command? Or is there a better way to do this: $strsql = "SELECT Name, Email FROM db"; $result = mysql_db_query("userdb",$strsql); $numrows = mysql_num_rows($result); for($i=0;$i<$numrows;++$i) { blah, blah mail($mailto, $mailsubject, $mailmessage, $mailfrom); } Thanks, Chris