my develop environment:
win7 64
python2.7.6 64
twisted 13.2

I have installed all modules twisted required.
but always throw an error:

```
    from twisted.internet import reactor 
cffi.ffiplatform.VerificationError: importing 'D:\\Python27\\lib\\site-packages\\cryptography\\_Cryptography_cffi_444d7397xa22f8491.pyd': DLL load failed: 

```

in another computer,I can use default reactor,but the error appeared when I used iocpreactor.and when use the default reactor,tcp mode,only one connection will work fine...

i have tried to change some old versions of modules,the problem remained the same 
what's wrong?