I have been running a number of upgrades recently and have had more than my share of failed installs on my terminal servers.  It started with failed add-ons and yesterday during a test install the SBO client uninstalled itself after a server-side hotfix and I had difficulty re-installing the client.
What i have found for both the client and several add-ons is: don't install from a network location.  Copy the files to the local desktop and install from there.