php.ini for UNIX sendmail????

Hi! What is the appropriate filepath with the flag command for the sendmail on the UNIX machine?? I send an email to yahoo and got the error message which I'm going to paste it here... --clip-- ----- The following addresses had permanent fatal errors ----- xyz@yahoo.com --- The transcript of the session follows --- ... while talking to mx2.mail.yahoo.com.: >>> MAIL From:<root@chevy> SIZE=40 <<< 501 Syntax error in parameters or arguments 501 xyz@yahoo.com... Data format error --clip-- One thing I know for sure is that the sendmail is working and that hte PHP code is working. I don't think I did the bad php command. Could it be the sendmail command be set wrong??? Thanks, FletchSOD