Please can you confirm that filename? It seems to be unique to your PC. The nearest match I have been able to find comes from a HijackThis log file submitted to a Polish website last November, and the only clue that gives is an annotation which says "Smart Engine".
\"C:\\Documents and Settings\\All Users\\Dane aplikacji\\ffbf87\\SMffb_2121.exe\"=\"C:\\Documents and Settings\\All Users\\Dane aplikacji\\ffbf87\\SMffb_2121.exe:*:Enabled:Smart Engine\"
There is also a fake email address (firstname.lastname@example.org) listed on Strakuv Antispam, a Czech website (http://elektrostraka.webzdarma.cz/Robotdestroyer.html?str=1000393)
And the sequence occurs a number of times in connection with websites which have, shall we say, a high likelihood of being rated Unsafe by SiteAdvisor. So it could be that the message you are getting indicates an infection of some sort. If you have a working version of McAfee, I think you should run a full scan as soon as possible, preferably from Safe Mode With Networking since it appears your McAfee download may have been blocked. Before you run the scan, check for updates from McAfee and Microsoft; best to be up to date with your protection.
After you've done that, run a Malwarebytes scan (download free from here).
Instant follow-up : as soon as I posted my reply I realised that "Smart Engine" may be not just a clue, but the answer.
Smart Engine is a rogue anti-spyware from the VirusDoctor family. This rogue is installed through the use of Trojans that impersonate video codecs or software updates required to watch videos online. When you run the program, though, it does not install any legitimate software but instead downloads and installs Smart Engine onto your computer without your permission of knowledge. While installing, Smart Engine will also create numerous harmless files that are meant to impersonate virus infections on your computer.
Please read this description of Smart Engine from BleepingComputer and see whether your PC has any of the symptoms of infection. If it has, follow the instructions further down the page for removal.
Thank you so very much. I am now able to download the new Mcafee antivirus software. Your help is very much appreciated.
Moved to Malware Disccussion > Home User Assistance and thanks Hayton for sorting this one out. ;-)