Error saving advert set policy

Hello all,

I am unable to modify or save any Patch Management policy and it gives me an error "Error saving policy".

Below is the log.

<event date="Aug 19 11:27:48 +00:00" severity="1" hostName="FRCP00VPD1060" source="Altiris.PatchManagementCore.Web.Policies.SoftwareUpdateTask.btlOKCancel_ApplyClicked" module="w3wp.exe" process="w3wp" pid="9924" thread="164" tickCount="70098078"><![CDATA[Error saving advert set policy: MS15-079.
**CEDUrlStart** :http://entced.symantec.com/entt?product=SMP&version=7.1.8400.0&language=en&module=6XKqUeZumHCpUAwBXN+eyM8WIzlu4ZkwO1uoRfEJV0/w8kt51zl4FWvwNm2uPgxw&error=-883311522&build=**CEDUrlEnd**

( Exception Details: Altiris.NS.Exceptions.AeXException: Unable to lookup the SID associated with the specified account ---> System.ArgumentException: String cannot be of zero length.
Parameter name: name
   at System.Security.Principal.NTAccount..ctor(String name)
   at Altiris.NS.Security.SecurityTrusteeProvider.LookupSidFromName(String scope, String name)
   --- End of inner exception stack trace ---
   at Altiris.NS.Security.SecurityTrusteeProvider.LookupSidFromName(String scope, String name)
   at Altiris.NS.UI.Controls.UserSettings.UserNameToSID(String user)
   at Altiris.NS.UI.Controls.UserSettings.SaveSettings(String user, String id, Object settings)
   at Altiris.PatchManagementCore.Web.Policies.SoftwareUpdateTask.btlOKCancel_ApplyClicked(Object sender, EventArgs e) )
( Exception logged from:
   at Altiris.Diagnostics.Logging.EventLog.ReportException(Int32 severity, String strMessage, String category, Exception exception)
   at Altiris.NS.Logging.EventLog.ReportException(Int32 severity, String strMessage, String category, Exception exception)
   at Altiris.PatchManagementCore.Web.Policies.SoftwareUpdateTask.btlOKCancel_ApplyClicked(Object sender, EventArgs e)
   at Altiris.WebControls.ButtonListControl.RaisePostBackEvent(String eventArgument)
   at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest()
   at System.Web.UI.Page.ProcessRequest(HttpContext context)
   at ASP.policies_softwareupdatetask_aspx.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
   at System.Web.HttpApplication.ApplicationStepManager.ResumeSteps(Exception error)
   at System.Web.HttpApplication.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)
   at System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr)
   at System.Web.HttpRuntime.ProcessRequestNoDemand(HttpWorkerRequest wr)
   at System.Web.Hosting.ISAPIRuntime.ProcessRequest(IntPtr ecb, Int32 iWRType)
 )

Thanks in advance!!