mail() on windows - problem

Hi all, Doing a little testing in advance of doing the scripting next week, I thought I'd try the mail() function. In php.ini, I have filled in the details of my SMTP server (University service) and the return address and I can't see anything else to configure. A simple script, called as a web page, contains the following script: <?php mail("gep1@stir.ac","Mailtest from php","message"); ?> and when I run this, I get an 'unknown' error and i [fairly obviously] don't get the email it should be sending. Is there something else to configure? I know that the smtp part is correct as I am mailing that way using both Lasso (NT) and Frontier (Mac) with no problems. HYCH, George in Edinburgh