Mail Problem

This is a repost due to the fact I still cannot resolve. The basic script below works on my development web server which sits on our company LAN. When I transfer the script to our isp hosted webserver, the script does not work. On my development server, the email is sent but on the production server there is no mail sent. I have also tried it using a fourth parameter mail($toaddress, $subject, $mailcontent, "From: it@ccmltd.co.uk\nReply-To:it@ccmltd.co.uk\nContent-Type: text/html; charset=iso-8859-1"); but this doesn't work either. Both webservers are Apache 1.3 running on a Linux 7.2 box. PHP version is 4.1.1. The logfile on the isp webservers seems to show that the message was delivered to me but I have mailmarshall software at our end that gives me history of all incoming emails good or bad and there is no sign of a mail coming from the isp webserver. Any ideas as to what I could check to get this working? If more info is needed I will happily supply. <?PHP $toaddress = "mark.colvin@ccmltd.co.uk"; $subject = "Enquiry via Web Site."; $mailcontent = "Customer Name: ".$name."\n" ."Position: ".$position."\n" ."Company Name: ".$company."\n" ."Address: ".$address."\n" ."E-mail: ".$email."\n" ."Tel No: ".$telno."\n" ."Customer Comments: ".$enquiry."\n"; mail($toaddress, $subject, $mailcontent); ?> **************************************************** This e-mail is intended for the recipient only and may contain confidential information. If you are not the intended recipient then you should reply to the sender and take no further ation based upon the content of the message. Internet e-mails are not necessarily secure and CCM Limited does not accept any responsibility for changes made to this message. Although checks have been made to ensure this message and any attchments are free from viruses the recipient should ensure that this is the case. ****************************************************