While a customer was trying to run a repair on ITMS via SIM (Symantec Installation Manager), during the initial configuration steps it fails with the following error:

A critical error occurred:
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. --->
Altiris.NS.Exceptions.AeXException: Root element is missing.--->
System.Xml.XmlException: Root element is missing.

Configuration failed while attempting: Configuring services..

ITMS 8.x

Empty web.config file due to a previous repair failure

Verify the following:

1. Check that the web.config (under ...\program files\altiris\notification server\web\) has content. See if it is not 0kb in size.
   If it is empty, grab the same file from another functional SMP server and replace it.
2. Then run again the reconfiguration process using SIM for the desired Solution/Suite.