While trying to upgrade to ITMS 8.1 RU7, during the process of configure Reports.config, it failed with the following entries:

Entry 1:
Symantec.Installation.ConfigureNS.StartCurrentTask: starting configuration task Configure NS Reports 8.1 RU7....
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Entry 2:
Failed to import the item from the file: ...\Program Files\Altiris\Reports\Config\Reports_RU.config

Item Import exception : 8b5afd3b-a6fc-4eae-bc7c-e558d4d173b3 = Altiris.NS.Reports.ReportsInstallation (a2d4bcae-2c0d-4288-a51b-5ff99f645d49)
[Altiris.NS.Exceptions.AeXItemImportException @ Altiris.NS]
...
An unexpected exception has occured during CreateInstance.
Assembly: Altiris.NS.Reports, Version=7.1.0.0, Culture=neutral, PublicKeyToken=cf9dd343b3008b86
...
Could not load file or assembly 'Altiris.NS.Reports, Version=7.1.0.0, Culture=neutral, PublicKeyToken=cf9dd343b3008b86' or one of its dependencies. The system cannot find the file specified.
[System.IO.FileNotFoundException @ mscorlib]

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Entry 3:
Failed to configure: ...\Program Files\Altiris\Reports\Config\Reports_RU.config

Item Import exception : 8b5afd3b-a6fc-4eae-bc7c-e558d4d173b3 = Altiris.NS.Reports.ReportsInstallation (a2d4bcae-2c0d-4288-a51b-5ff99f645d49)
....
An unexpected exception has occured during CreateInstance.
Assembly: Altiris.NS.Reports, Version=7.1.0.0, Culture=neutral, PublicKeyToken=cf9dd343b3008b86
....

Could not load file or assembly 'Altiris.NS.Reports, Version=7.1.0.0, Culture=neutral, PublicKeyToken=cf9dd343b3008b86' or one of its dependencies. The system cannot find the file specified.
[System.IO.FileNotFoundException @ mscorlib]

 

ITMS 8.x

Bad assembly references

Since the error messages were referring to:
assembly 'Altiris.NS.Reports, Version=7.1.0.0, Culture=neutral, PublicKeyToken=cf9dd343b3008b86'

Try the following:

1. Create a dummy folder called "v4.0_7.1.0.0__cf9dd343b3008b86" (just copy the same folder already present (in this case it was called "v4.0_8.1.4528.0__cf9dd343b3008b86" and rename the copy) under "C:\Windows\Microsoft.NET\assembly\GAC_MSIL\Altiris.NS.Reports")
   OR
   grab the missing assembly from another server with the same version
   OR
   run the MSI related to the dll manually to get the missing dll. 
   msiexec /i "C:\Program Files\Altiris\Symantec Installation Manager\Installs\Altiris\altiris_reports_x_x_x64.msi" skipaim=1
2. Stop IIS (iisreset /stop) and Altiris Services
Go to "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files\" and delete the "Altiris" folders
3. Restart IIS (iisreset /start)
4. Run a reconfigure on the installed product through SIM.

Note: 
In some instances, running the MSI associated with the missing assembly works in getting the missing MSI but UAC (User Access Control) may be blocking getting it in place. You can disable UAC in the registry, reboot, and run the upgrade process one more time.