During installation of Client Management Suite I got this exception thrown out in Altiris Log Viewer. After this Exception gets thrown out there follow up many other exceptions like "AeXSvc service was unable to restart", causing installation to fail.

Before installing CMS, netstat shows that on port 50121 there is a TCP listening socket, but when installation starts this socket does not appear anymore in netstat(also process AtrsHost.exe is not in Task Manager anymore).

Netstat before installation:

 TCP    0.0.0.0:50121          0.0.0.0:0              LISTENING       5436
 [AtrsHost.exe]

And Log output:
 

Log File Name: C:\Program Files\Altiris\Notification Server\Logs\a.log
Priority: 1
Date: 7/10/2009 5:40:11 AM
Tick Count: 13540937
Host Name: ALTIRIS-CLIENT
Process: w3wp (4864)
Thread ID: 11
Module: w3wp.exe
Source: Altiris.TaskManagement.ClientTask.*
Description: BaseXmlCallback Exception: System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 127.0.0.1:50121
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)
at Altiris.DotNetLib.Sockets.SecureRemoting.SecureRemotingClient.EstablishConnection()
at Altiris.DotNetLib.Sockets.SecureRemoting.SecureRemotingClient.AttempSendRequest(String service, Hashtable input)
at Altiris.DotNetLib.Sockets.SecureRemoting.SecureRemotingClient.SendRequestI(String service, Hashtable input)
at Altiris.DotNetLib.Sockets.SecureRemoting.SecureRemotingClient.SendRequest(String service, Hashtable input)
at Altiris.ClientTask.Server.HttpHandlers.WebClientApiManager.ProcessGetTasksRequest(XmlTextWriter wr, NameValueCollection queryValues, Stream requestStream, Int32 contentLength)
at Altiris.ClientTask.Server.HttpHandlers.GetTasks.WriteResponse(XmlTextWriter wr)
at Altiris.TaskManagement.Common.XmlHttp.BaseXmlXmlHttpCallback.WriteResponseRaw(XmlTextWriter xwr)
at Altiris.TaskManagement.Common.XmlHttp.BaseXmlHttpCallback.ProcessRequest(HttpContext context)