Installing php_zmq zeromq on XAMPP with PHP 5.6 as a service

May try install VS2010 C++ redistributable

Reference: http://stackoverflow.com/questions/4718262/zeromq-dllnotfoundexception-using-net-bindings

Sorry, try Visual Studio 2013 C++ redistributable

Depending on your OS and version of zeroMQ you may need a different version of the Visual Studio C++ redistributable.
Reference: http://zeromq.org/distro:microsoft-windows