ctfmon.exe needed?

The last week or so everytime I boot up my hp pc running xp a pop up window from my Ad-Aware program tells me:
An attempt to alter a protected object has been detected.
(Attempt to add a registry value.)
Root:HKEY_CURRENT_USER
Key:Software\Microsoft\Windows\Current Version\Run
Value:ctfmon.exe
Data:
New Data:C\WINDOWS\system32\ctfmon.exe

Then it asks me to accept or block.I have blocked everytime but my question is what is ctfmon.exe and why is this popping up now and not before.No new programs have been installed.Will it do any harm to allow it to add the registry value?

Thanks in advance for any info you can supply me on this.

Just looked at my event log on Ad-Watch and see that despite my blocking it,this registry value has been added!!!

I run Ad-Aware,Spyware Doctor and avast! Antivirus on this machine and all scans come out clean.

 

http://support.microsoft.com/kb/282599

 

I did see that article when I did a search on ctfmon.exe but I don't run any Microsoft Office programs.Why would this all of a sudden start popping up?

Is the changed or added value showing the right path?

I do recall seeing this in the startup menu before,just wondering if the added registry value is legit.

 

Yes, that is the legitimate filepath. Won't hurt anything to just allow the change.