Cannot store values into memcache-PHP

Question

When I'm running PHP+memcache, I cannot store values into memcache. My PHP version is 5.4.12 and memcache version is 3.0.8

I am setting ini_set('display_errors', true); and error_reporting(E_ALL); and getting the notice:

Notice: MemcachePool::set(): Server 127.0.0.1 (tcp 11211, udp 0) failed
with: Network timeout (0) in xxx/test/my_test.php
on line XX

and when I try to use the "telnet 127.0.0.1 11211". It show like this:

$ telnet 127.0.0.1 11211
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
stats

there's no any response... Does anyone have any idea...