Exchange 5.5 and mail() problems

[Anon]

Hi again,
I am using IIS / Win NT 4.0 (SP 6.0a) / and Sxchange 5.5 server to 'attempt' to send email from a generated form.

I can send the email successfully when I send to someone in my Domain, by if I try to send to "Yahoo.com" (for example) the email page genereates an error:

Here's the text -
Warning: Server Error in F:\WWWRoot\InternetHome\costresult.php on line 27

Now, "Line 27" is simply -
mail($mailTo, $mailSubject, $mailBody, $mailHeaders);

Like I said, this all works fine for my own domain addresses, but fails for email address out of my domain.

I gave up and posted after looking through other support forums here for several hours (in between troubleshooting/brainstorming attempts)

Thanks!
Jason

[Anon]

I have that error when i try to send an email to a none exsisting user with a local domain.