Cannot post the string "curl_exec($curl);" to wordpress without a 503 errror

[davedash]

I've been writing a tutorial that involves PHP's curl functions. Each time I posted I got a 503 Service unavailable. I narrowed it down to the text:

curl_exec($curl);

I created a new post with only that text and sure enough it cause a 503 error.

What relevant details are needed? This is in WP 2.1, running on PHP5.

mod_security is runnning on your server.