Dears,
I am getting continuous error message in event viewer like as follows.Can u help me to solve this? Our Dnn 5.6.2 site is working on serevr 2008 R2 machine.I added the user "Network Service" and gave full control to the DNN folder.

ERROR 1

UpgradeNet: Upgrade to .NET 4.0 failed. Error reported during attempt to update:Error: Object reference not set to an instance of an object. at DotNetNuke.Services.Installer.XmlMerge.UpdateNode(XmlNode rootNode, XmlNode actionNode) at DotNetNuke.Services.Installer.XmlMerge.ProcessNode(XmlNode node) at DotNetNuke.Services.Installer.XmlMerge.ProcessNodes(XmlNodeList nodes, Boolean saveConfig) at DotNetNuke.Services.Installer.XmlMerge.UpdateConfigs() at DotNetNuke.Services.Upgrade.Upgrade.UpdateConfig(String strConfigFile, Version version, String strReason)
Server Name: HUDHUD


ERROR 2

AssemblyVersion: 5.6.2
PortalID: -1
PortalName:
UserID: -1
UserName:
ActiveTabID: -1
ActiveTabName:
RawURL: /
AbsoluteURL: /
AbsoluteURLReferrer:
UserAgent:
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: f0095f39-1249-4fae-8d2e-c8c224f1e87c
InnerException: Object reference not set to an instance of an object.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: DotNetNuke.Services.Installer.XmlMerge.UpdateNode
StackTrace:
Message: System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Services.Installer.XmlMerge.UpdateNode(XmlNode rootNode, XmlNode actionNode) at DotNetNuke.Services.Installer.XmlMerge.ProcessNode(XmlNode node) at DotNetNuke.Services.Installer.XmlMerge.ProcessNodes(XmlNodeList nodes, Boolean saveConfig) at DotNetNuke.Services.Installer.XmlMerge.UpdateConfigs() at DotNetNuke.Services.Upgrade.Upgrade.UpdateConfig(String strConfigFile, Version version, String strReason)
Source: