Such a message is an indication that your PC is host to some unwanted malware.
Check your system using your preferred antivirus application making sure first
that you are using an updated current set of viral reference signatures.

This would be a good time to download yourself a copy of the free Ad-Aware 6.0
from Lavasoft (http://www.lavasoftusa.com/software/adaware/) and also SpyBot
Search & Destroy (http://www.safer-networking.org/) and use them to check your
system for other commercial parasites remembering that they are only as good
as when you last updated their reference files.  I also use a program called
BHODemon (http://www.definitivesolutions.com/bhodemon.htm that checks for
unwanted Browser Help Objects and SpywareBlaster
(http://www.wilderssecurity.net/spywareblaster.html) which can help prevent
some parasites getting a grip on your PC.

Then  there is CWShredder
(http://www.zerosrealm.com/downloads/CWShredder.zip or
http://www.spywareinfo.com/~merijn/files/cwshredder.zip) which is the best way
of getting rid of the many forms of the CoolWebSearch hijacker details of
which can be found at http://www.spywareinfo.com/~merijn/cwschronicles.html
and also http://www.pestpatrol.com/pestinfo/c/cws.asp..

Finally if you still continue to experience problems download a copy of
HijackThis from (http://www.spywareinfo.com/~merijn/downloads.html).  Create a
folder called hijackthis on C: and copy the file you downloaded to that
folder.  Close as many applications as you can including all instances of
Internet Explorer and then run hijackthis.exe and post back the log, provided
that it isn't too long, to this thread, otherwise to the HijackThis Forum at
http://www.spywareinfo.com/forums/ and hopefully this will enable someone to
identify the cause of your problem.
--?
Mike Maltby MS-MVP
mcmaltby@hotmail.com