To resolve this, close FIMS, then right-click on the FIMS icon and select Run as Administrator. This will allow the .Net assemblies configuration to be updated on the workstation. This will need to be done on every machine with this message. The message should then disappear, if it re-appears again then that means that .Net was not updated.
If you get a promsgs error when running as admin, see the following article:
If the steps above do not work, then do steps 4 and 6 in the following article: