RITT is a virus written in Pascal and compressed with PKLITE 1.15. It is not common at all, but it is sometimes reported since McAfee Scan has had a false positive on it.
Scan gave an unnecessary alarm on some files packed with PKLITE 1.15. Examples of such files are DWCOMM and DWCONFIG from the Doorway package.
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.