Im having this error since the first few days of my installation. Im running windows 2003, sql server 2000 and DNN 4.0.2. Im have no idea what caused this error. Sometimes it is okay, sometimes this showed up. Would appreciate if someone can help me on this. Thanks.

Server Error in '/hostportal402' Application.
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Security Exception
Description: The application attempted to perform an operation not allowed by the security policy.  To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. 

Stack Trace:

[SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.]
   System.Web.Configuration.MetabaseServerConfig.MapPathCaching(String siteID, VirtualPath path) +3492186
   System.Web.Configuration.MetabaseServerConfig.System.Web.Configuration.IConfigMapPath.MapPath(String siteID, VirtualPath vpath) +9
   System.Web.Hosting.HostingEnvironment.MapPathActual(VirtualPath virtualPath, Boolean permitNull) +163
   System.Web.CachedPathData.GetConfigPathData(String configPath) +382
   System.Web.CachedPathData.GetConfigPathData(String configPath) +243
   System.Web.CachedPathData.GetConfigPathData(String configPath) +243
   System.Web.CachedPathData.GetConfigPathData(String configPath) +243
   System.Web.CachedPathData.GetConfigPathData(String configPath) +243
   System.Web.CachedPathData.GetVirtualPathData(VirtualPath virtualPath, Boolean permitPathsOutsideApp) +132
   System.Web.HttpContext.GetFilePathData() +27
   System.Web.HttpContext.GetConfigurationPathData() +26
   System.Web.Configuration.HttpConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String configKey) +36
   System.Configuration.ConfigurationManager.GetSection(String sectionName) +107
   System.Configuration.PrivilegedConfigurationManager.GetSection(String sectionName) +32
   System.Xml.Serialization.XmlCustomformatter.get_Mode() +47
   System.Xml.Serialization.XmlCustomformatter.FromDateTime(DateTime value) +4
   System.Xml.Serialization.XmlSerializationWriter.FromDateTime(DateTime value) +13
   Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterLogInfo.Write3_LogInfo(String n, String ns, LogInfo o, Boolean isNullable, Boolean needType) +381
   Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterLogInfo.Write4_log(Object o) +102

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Version Information: Microsoft .NET Framework Version:2.0.50727.42; ASP.NET Version:2.0.50727.42