first question form my original replay was:
this question remains un answered....
The response form the SMTP server:
string(77) "mail(): SMTP server response: 550 No such user here"
means one of 2 things:
a) the server you entered requires authentication.
b) the from address you entered is not a valid address for your domain
You may need to enable the option to pass the From Address as an extra parameter, for some hosts this is needed.
you may need to opt to use pear Mail for SMTP instead of the standard mail object.
your host may have other requirements in place for sending email from a php script. I don't know since i don't know who your host is...