Adobe Flash Player and Reader software installations have caused problems in the past, already. Often Flash Player installation had to be done couple of times. Reader installation with a download manager and Nosso is heavy.
Previously, the clearest way has been first download the installation program and then install it separately. For example, Firefox does not attempt to install on your own. As of Flash Player version 10.3.183.5 only a stub is for download on Adobe’s website directly, which stub then would apply for the actual installation, unless that stub wouldn’t fail with a proxy server.