This is not a virus or any other kind of malware.
Some people have been wondering about mysterious entries appearing to their datebook to date 25 December 2030. The entries having title Santa and attached note containing a number (usually 0).
The Santa entries are an Easter egg (a hidden functionality) in wordsmith program versions 1.0c or older. For some reason the programmer thought it would be fun to put mysterious entries into the datebook.
This behaviour is harmless and shouldn't cause any problems. Blue Nomad has removed the Easter egg in the word smith version 1.0d.
Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.