The problem could be solved after adding the specific machine in the dmskrnl.cfg file.
The label on the left does not matter. You can add something like this:
PWCLIENT = 10.9.4.15 255.255.255.0
The first number is the ip address of the client; the second number is the subnet mask

Windows XP has an Internet Connection Firewall feature. After you have installed some hotfixes this feature is enabled automatical ly. As a result service ports are blocked. In order to open the ports, please go to My Network Places—>Local Area Connection—- >Properties—–>Advanced, here uncheck the “Internet Connection Firewall” checkbox. Reboot the system.

If you have WinXP S ervice Pack 2, as an alternative to disabling Internet Connection Firewall, you may instead add the SentinelLM service as an excep tion that does not get blocked. To do this, follow these instructions:

Click on Control Panel –> Windows Firewall.
On the Windows Firewall window, click on the Exceptions tab.
Click the Add Program button.
Click the Browse button on the Add a Program window and browse to your SentinelLM install directory–the default for version 7.2 is C:\Program Files\Rainbow Technolog ies\SentinelLM 7.2.0 Server\English
Select the lservnt.exe file and click Open.
You should now see lservnt.exe in the Progra ms and Services listing in the Exceptions tab.
Click OK and close out of the Windows Firewall window.
Reboot your computer.< CR>
You should now see your server listed if you look under Subnet Servers when running WLMAdmin.