This is just an informational message and occurs for Windows servers (clustered or not) and Windows workstations. Windows detects the LINK activation for the Ethernet 10/100BaseT adapter. But it is a very good indication for situations when there is a cable problem or switch/hub issue.
In my case this problem was caused by a switch problem. I replaced the switch with a new one and the event disappeared.
I was getting this event every few seconds after I recovered my corrupted hard drive. A router restart solved the problem.
I came across this error on a system. The System Log was full of these events. I noticed that the wireless network icon was indicating that Windows was trying to acquire a network address. I had changed the WPA-PSK password recently and had not updated it on the machine. Every time the machine tried to update (about every 10 seconds) it recorded an error. I updated the password and the error has gone away.
I was getting literally thousands of 4201 error messages on my server over a three-week period. It turned out that the switch was failing. After I replaced the switch, the problem ceased to reappear.