When installing products/solutions within SIM the download progress page seems to hang. The progress bar/indicator stays at 0% downloaded and no errors appear in the user interface.
No visible errors in SIM interface
When looking at the SIM Installation logs you will see that download of msi files are timing out and that the installer is retrying the download in a repetitive cycle.
Customer was behind a proxy server, where it did not seem to properly pass through to download files. The SIM configuration settings were set to utilize a proxy server, but due to restrictions on customer network we were not able to test this with internet explorer manually.
An alternate option for this is to download the msi files that are timing out on a different machine and copy them over (Downloaded files can be located in \Program Files\Altiris\Symantec Installation Manager\Installs\Altiris).
The following two suggestions may also prove useful;
Add lindon.extranet.altiris.com and www.solutionsam.com (cyclical ip range!) to pass through proxy servers without requiring authentication/traffic inspection.
Launch Internet Explorer with Run As option under the Application Identity that SMP/NS is running as and attempt to access/download the MSI file that is timing out in the SIM Install logs.
This should indicate if there is any proxy information/warnings that are thrown but not understood by the SIM installer application.