what's wrong with this validation code?

[sridharao]

I have the following code being used for validating a form:

if (isset($_POST['AddEntry'])) {
    $emai = stripslashes($_POST['YourEmail']);
    $namm = stripslashes($_POST['YourName']);
    $commt = ($_POST['YourComment']);
    if (!preg_match("/[A-Za-z]*/", $namm)) {
      die ('<p align="center">Sorry, Please enter text without any symbols or special characters.</p>');  //THIS ISN'T WORKING
    }else{
      $nam = $namm;
   }
    if (!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$",$emai)){
        die ('<p align="center">There is something wrong with your email ID, please check it.</p>');
    }
    list($userName, $mailDomain) = split("@", $emai);
    if (!myCheckDNSRR($mailDomain, "MX")) {
        die ('<p align="center">Sorry, this email ID failed validation. Please provide correct email ID.</p>');
    }    
    if (!preg_match("/[A-Za-z]*/", $commt)) {
      die ('<p align="center">Sorry, Please enter text without any symbols or special characters.</p>');
    }else{
      $comt = $commt;
   } 

this is the function to check dnserror:

function myCheckDNSRR($hostName, $recType = ''){
    if(!empty($hostName)) {
        if( $recType == '' ) $recType = "MX";
            exec("nslookup -type=$recType $hostName", $result);
            foreach ($result as $line) {
                if(eregi("^$hostName",$line)) {
                    return true;
                }
            }
        return false;
    }
return false;
} 

I found this script on the net for windows based servers, this script is failing despite providing a valid domain name.