Ready proxy server. WIN7x64 tested. Compiled  "sammy007's proxy (https://github.com/sammy007/ether-proxy)"
1. https://files.fm/u/utd7v3pq
2. Edit config.json change string "url": "http://pool.pooleth.com/pool/YOUR_pooleth.com_NAME/rig1" See you settings on site.
3. RUN proxy_run.bat
4. RUN ethminer.exe -G -F http://127.0.0.1:8545/miner/1/local --farm-recheck 100
*  "--farm-recheck 100" Configurable
* You can use the option --rpc to connect to your proxy with some rigs. If they are available on the network.
* See your stats in browser. address http://localhost:8080 , https://www.pooleth.com/workers.php
http://i73.fastpic.ru/big/2016/0118/d9/477d8ecd7c6b7b982d12536cd56064d9.jpg

And the question Why do sometimes "rejected"?
Difficulty: 5 000 000 000 it Normal?