A number of things could affect your software's update manager: 1) slow internet connection (some applications could be hogging the bandwidth) 2) the firewall might be blocking the application from connecting online and 3) the update site could be experiencing overload
First, make sure you have an active internet connection. If you do, this can sometimes happen if you have a virus of some sort on it. Get and run an antivirus software. If that doesn't work, and contact the manufacturer.
