Just a little warning - Cognos Express 10.2.1 Performance Modeler does not work if you have MS Internet Explorer 11 installed (it's not in supported environments either). It doesn't work even if you run it from Firefox or localy (and have IE 11 installed) - the client obviously uses IE libraries that changed with the last update.
Performance modeler itself runs, but if you try to use Guided Import, Create Process and other functions, the client just hangs without any error message, which makes finding the real prolem somewhat tricky.
After uninstall of IE 11 update, everything starts to work smoothly again.
This issue is worth fixing as MS Server 2012 R2 comes with IE 11. If there's more assistance needed, I'll gladly provide screenshots.