Socket: Unknown Error

Configuration.
Environment 802 ESP10 with web products on same level.
Portal 3.0.10.686
Windows 2000 SP4 IIS5, Tomcat 3.2.3

Since few weeks we are experienced stability problems with web products. Initially we think recently win2k hot fixes had relation with the problem. Hot fixes were removed and back to work. But problem came again. After rebooting system, process flow services goes up and stay no more than two hours and gone. Ports were checked and see services running, but socket problems remain.

After further investigation, we prepared a new machine with exact copy of our production and upgrade to Windows 2003. We are testing now, and doest not get the error.

Any idea about socket errors?