Mike,
ICMP.DLL (Internet Control Message Protocol) is a Microsoft file used to facilitate pinging of IP addresses that I believe is installed with the Windows O/S. I suggest you try unregistering and then re-registering that DLL, by issuing the following two commands in the Start > Run dialog window:
regsvr32 c:\windows\system32\icmp.dll /u
regsvr32 c:\windows\system32\icmp.dll
Perhaps that will be all you need to do. If it doesn't work, but if you manually updated Windows XP to Service Pack 2, then you might try reinstalling the service pack to see if that resolves your problem. Googling for info about ICMP.DLL as well as searching the Microsoft Knowledge Base hasn't readily pointed to any way of updating that one file specifically. The version I have running on the PC I'm at currenly is 5.1.2600.2180. If you have something older (lower version number) than that, perhaps that is the problem, and Service Pack 2 should correct the situation I believe. If you're running a native Windows XP/SP2 installation that came delivered on your PC or on a CD, then you may need to just try copying ICMP.DLL from another source onto your PC. To save you some time finding another copy of the file, I've uploaded a zipped copy to <
http://ambress.com/icmp.zip>. If you go this route, just copy it to the system32 directory and register the DLL as per the 2nd command given above.
Hope that helps,
Daryl