Not being able to set cookie?

caution:
Caution:Cannot transform header details – headers by now sent through (output started at /Applications/MAMP/bin/mamp/mydata/cooki in /Applications/MAMP/bin/mamp/mydata/cooki on line 6

This hails from the PHP guide book:

setcookie() defines any cookie being sent along with the rest with the HTTP headers.Just like other headers, cookies have to be sent just before any output from your script (this may be a protocol restriction).This requires you place calls to the function earlier than any output, including along with tags as well as any whitespace.

So ones code should look like:

.