This clearing of ARP cache error occurs when Routing and Remote Services is enabled. Routing and Remote Services is almost unnnecessary and can be turned off unless you know that you are using it.disable Routing and Remote Services:

• Click the <Start> button
• Click the <Control Panel> button
• Switch to "Classic View" if you are in "Category View"
• Click <Administrative Tools>
• Click <Computer Management>
• Double-click <Services and Applications>
• Double-click <Services>
• Scroll down to <Routing and Remote Services>
• Double-click <Routing and Remote Services>
• Examine the "Startup Type"
• The options are "Automatic", "Manual", and "Disabled"
• Set the "Startup Type" to "Disabled"
• Examine the "Service status"
• Make sure that the service status is Stopped. If it is not Stopped, click the <Stop> button
• Click the <OK> button

Now, try clearing the ARP cache again and it should complete with no error messages
Found it on the net .... hope it solves ur problem too