Cant get XBMC Argus plugin to work

I have a Argus server/client on a windows XP computer. On this computer xbmc Argus plugin works fine with default settings.
But i am trying to get XBMC argus plugin to work on a nother computer with no luck. I have tryed with two different computers with same result . One with windows 7 and another with windows XP.
On both computers the Argus client is working ok.
The computers are on the same network and firewall is off.
The server computers IP is 192.168.0.107 and the user name is Marcus and there is no password
here is part of the XBMC log from the windows / computer

21:49:45 T:2592 INFO: AddOnLog: ARGUS TV client: Connect() - Connecting to http://192.168.0.107:49943/
21:49:45 T:2592 DEBUG: AddOnLog: ARGUS TV client: URL: http://192.168.0.107:49943/ArgusTV/Core/Ping/52
21:49:45 T:2592 DEBUG: CurlFile::Open(08758D30) http://192.168.0.107:49943/ArgusTV/Core/Ping/52
21:49:45 T:2592 INFO: XCURL::DllLibCurlGlobal::easy_aquire - Created session to http://192.168.0.107

21:49:55 T:2592 ERROR: AddOnLog: ARGUS TV client: can not write to http://192.168.0.107:49943/ArgusTV/Core/Ping/52
21:49:55 T:2592 ERROR: AddOnLog: ARGUS TV client: Ping failed... No connection to Argus TV.
21:49:56 T:2592 DEBUG: AddOnLog: ARGUS TV client: URL: http://192.168.0.107:49943/ArgusTV/Core/Ping/52
21:49:56 T:2592 DEBUG: CurlFile::Open(087FA738) http://192.168.0.107:49943/ArgusTV/Core/Ping/52

What could be the root course of this problem ?