Is the failure point during the download from Symantec or the distribution to your distribution center locations?
You can choose to manually download/distribute as opposed to scheduling the same. Depending on how you have set up your environment, you can install LUA on one computer, download and distribute to the distribution center location onthe same computer, then copy the contents of the distribution center location to external media and setup another LiveUpdate server elsewhere.
We've had many customers ask for bandwidth throttling and we expect to provide a solution in the near future.