Exec(), system, cURL and PayPal

[rogair]

I'm trying to build in PayPal as an alternative payment method on some sites. I want to use IPN as these sites have downloadable product so I must automate the system. I use cURL to run the IPN post. So I have

exec("curl -d 'bigolnastyvarstring' https://www.paypal.com/cgi-bin/webscr", $authorize, $ret);

but get nothing in $authorize[0]
$ret is returning 127 but I don't know what that means.

I have also tried
$authorize=system("curl -d 'bigolnastyvarstring' https://www.paypal.com/cgi-bin/webscr")

And still get nothing.

When I run
curl -d 'bigolnastyvarstring' https://www.paypal.com/cgi-bin/webscr
from the command prompt I get the proper response. Any clues?

BTW my cURL thing works for CC transactions and I've been using it for two years.

[rogair]

Ugh, ok the code is ok. I just ran it in my SSL directory and it worked just fine. So it's a config issue instead.