Header error - cookie related

[smallcompany]

I have PHP script being called from HTML by php include.

.httaccess in the folder where the HTML and script are, is one line only:

addtype application/x-httpd-php .php .html

and parsing works fine, but with "Headers already sent" error.

The line where PHP error is pointing to is in relation to "setcookie"

If I turn the cookie check OFF (in the script), everything works fine.

Now, why would cookie cause this?

Thanks

[cameraman]

Cookies are sent with the header, so you have to set them before any other output from your script.