I want to install the Crypt_DiffieHellman PEAR package, that gives me the following error: pear/Crypt_DiffieHellman requires PHP extension "gmp" So I installed the gmp extension (using MacPorts' "php5-gmp"), both php -m and extension_loaded('gmp') indicate that the extension is loaded. However I still get the PEAR error when I try to install the package. Am I missing something here? Or is this a (known) bug with the package/PEAR installer?