SMTP error with mail()

[luciform]

I'm getting the following error:

 

Warning: mail() [function.mail]: Failed to connect to mailserver at "localhost" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set() in (file path)

 

I'm sure this error has been posted before, but I've searched and can't find a solution. I'm running XAMPP 1.7.3 with the Mercury/32 mail server v.4.72, which IS set to permit SMTP relaying of non-local mail. Is there anything I can change in php.ini, or anywhere else for that matter, to solve this?

 

I'm tearing my hair out with this... If I can just get it to send out this email, my project is finished, but I've been wrestling with this mail() function for about 3 hours. 

 

Any help would be appreciated.