I noticed something similar and at times, you may have to unblock the installer first before copying it over to the client (right click, select properties and at times you have an "Unblock" button). This mostly happens if you download an installer from the Internet (i.e. standalone installers for JRE, Flash, etc).
An alternative to find out what is happening is to run the script / command in console user session against a single machine and you will be presented with either an error, UAC prompt or other messages.
As the others mentioned, some feedback would be appreciated,
-BBC