Oracel Policy Modeler Debugger is not working with Internet Explorer 10. You can still use it to author and compile rules, but debugger with windows just hangs.
There is no official fix for this yet, so your only option is to uninstall IE10 if you can. In windows 7 go to Control Panel->Programs->Programs and features ->View installed updates->Internet Explorer 10->Uninstall.
BTW, OPM is not working with Office 2013 either.