Community Edition 10.3 failing to install

I've downloaded CE, got an email with the serial for it, applied it when the dialogue showed up during the installation, everything's fine. The installation process starts, progress bar "Installing Main Application Files", shows up and... error after error:

"..\bin\   An error occured while trying to copy a file: The source file is corrupted."

and so on, tons of errors for the files. What can be the problem and how to fix?