Pushpool + Bitcoind returns HTTP request failed 500

Error:

[2013-11-17 10:17:35] json_rpc_call failed, retry after 30 seconds  
[2013-11-17 10:18:09] JSON-RPC call failed: {  
   "code": -2,  
   "message": "upstream RPC error"  
}  
[2013-11-17 10:18:09] json_rpc_call failed, retry after 30 seconds  

Pushpool server log:

root@xxxxxxxx:/usr/local/sbin# ./pushpoold --debug=2 --stderr --  foreground --config=/usr/local/sbin/server.json  
 JSON protocol request:  
{"method": "getwork", "params": [], "id":1}  

About to connect() to 127.0.0.1 port 8332 (#0)  
   Trying 127.0.0.1... * TCP_NODELAY set  
 connected  
 Connected to 127.0.0.1 (127.0.0.1) port 8332 (#0)  
 Server auth using Basic with user 'username'  
 POST / HTTP/1.1  
Authorization: Basic dXNlcm5hbWV2YXN5YTpwYXNzd29yZHZhc3lhMTQ=  
Host: 127.0.0.1:8332  
Accept: */*  
Accept-Encoding: deflate, gzip  
Content-type: application/json  
Content-Length: 45  

 The requested URL returned error: 500  
 Closing connection #0  
[2013-11-17 11:16:20.142159] HTTP request failed: The requested URL returned error: 500 

Just wait the bitcoind sync with the bitcoin network (9GB actually), and after you can use it.

du -ksh ~/.bitcoin/ will give the size.