Warning: mail() [function.mail]: "sendmail_from" not set in php.ini

when trying to login to my Zencart admin I get the following error immediately after entering username and password

- Warning: mail() [function.mail]: "sendmail_from" not set in php.ini or custom "From:" header missing in D:\Inetpub\asianfilmsource\sauce_cart\adminfoldername\login.php on line 33

I also get ERROR_SECURITY_ERROR displayed next to the login button

I have two zencarts setup on same server, the other one I am able to login so I dont believe there is an issue with php.ini and I didnt see any obvious differences between the two login.php files

any and all help and assistance would be appreciated

Patrick