The online documentation at www.php.net under "mcrypt" states in example #2 that you should use the line:

$td = mcrypt_open_module (MCRYPT_TripleDES, "", MCRYPT_MODE_ECB);

However the function mcrypt_open_module does not exist, atleast in my installation of 4.0.2.  However This line does work:

$td = mcrypt_module_open(MCRYPT_TripleDES, "", MCRYPT_MODE_ECB, ""); 

Is this a typo in the online documentation or a configuration error?  I posted a user note against "mcrypt" in the quick ref section.

I installed libmhash(0.8.2), libmcrypt(2.2.4), and mcrypt(2.5.4), ran ldconfig to update all the libraries, and configured.