When doing anything from my web site that involves generating an email (e.g., registering new user on site, using Contact Us, sending email to customer from admin), I receive the below error:

Warning: mail(): "sendmail_from" not set in php.ini or custom "From:" header missing in C:\hshome\topbull\comancheangus.com\catalog\includ es\classes\email.php on line 500

Warning: Cannot modify header information - headers already sent by (output started at C:\hshome\topbull\comancheangus.com\catalog\includ es\classes\email.php:500) in C:\hshome\topbull\comancheangus.com\catalog\includ es\functions\general.php on line 29

I searched for a php.ini, but that does not seem to exist. I looked in the email.php file and found several sections with "from", but do not know what to do with them.

In the admin module, I have set the email address for "E-mail Address", "E-mail From", and "Send Extra Orders To". Email transport method is SMTP and Email Linefeeds is CRLF. HTML and DNS are false. Send emails is True.

I found a similar issue on the forum for 1.7, but no resolution. Help !