Printer Software only begins to download and then I am asked to try again later.

Brother MFC8460N and Canon MG5220 printers. Both appear to be compatible for updates. Using OSX10.8.2. I keep getting a popup asking me to intall software for my printers. When I try to install it starts to install and then another popup says to try again later. Have tried several times over the past 3 weeks to complete this. Any help gratefull accepted.