Problem Using mcrypt_encrypt with $iv

[Anon]

Can anyone help me with this

$decryptdata = mcrypt_encrypt(MCRYPT_DES, $key, $source,MCRYPT_MODE_CBC, $iv);
echo("complete...<br>Data:$source<br>Key:$key<br>Output encrypted:$decryptdata");

I've tried the to techniques to create $iv and they both fail

$cipher = MCRYPT_DES;
$block_size = mcrypt_get_block_size ($cipher);
$iv = mcrypt_create_iv ($block_size, MCRYPT_DEV_RANDOM);

and

srand((double) microtime() * 1000000);
$iv = mcrypt_create_iv(32, MCRYPT_RAND);