logs are on the client in the folder C:\Program Files\Altiris\Altiris Agent\Logs
I had a similar problem, but it was too long path (too many subdirectories)
the error in the log is something like this: Error while downloading package: No package sources returned by server (-2147023728)]]></event>
I have change path on the site/pack-server in All Resources => Package => Software Package =>edit the softeare packet => and change Package Destination Location on package servers (leave blank for default): to D:\sw\cs5st
and you need to change it on the policy in advanced => the location to C:\sw\cs5
and it solved my problem for Adobe Design Standard CS5 DK