Hi,
please check this KB where similar issue is described
https://support.symantec.com/en_US/article.TECH224409.html
Your log also contains same information:
<event date="04/28/2015 13:43:26.7845324 +07:00" severity="1" hostName="WIDCB2I004" source="Altiris.Web.NS.Agent.GetPackageInfo.HandleRequest" module="w3wp.exe" process="w3wp" pid="3068" thread="62" tickCount="443386"><![CDATA[GetPackageInfo.HandleRequest
The access is forbidden for unmanaged resources.
Thanks,
IP.