Did you even read reflash guide? It clearly says where to download files. Don't skip lines...
"On Windows, open a Command Prompt with Administrator permissions (with UAC, right-click Command Prompt and select Run as administrator). On Linux, open a root shell (sudo -i/su). Change to the directory containing the firmware images you downloaded. On Windows, run set PATH="C:\Program Files\Nokia\Flasher;%PATH%" in order to add Flasher to the system path."