Hi,
I think it may be because your bitcoind client is not listening for JSON-RPC connections except on localhost.
From the manpage for the default settings
rpcallowip='192.168.1.*'
By default, only RPC connections from localhost are
allowed. Specify as many *rpcallowip=* settings as you
like to allow connections from other hosts (and you may
use * as a wildcard character)
So for security you should probably set rpcallowip=yourserverip
You could also set it to * just to test.
good luck.