Perhaps its referring to the specific version of the desktop modeler that is not installed? Otherwise this is not something I have encountered before, in which case filing a ticket might provide some clarification :)
I had the same issue on my home machine. Correct modeler version would open about 1.5 seconds after that message so it never bothered me enough to fix it. I recently uninstalled several old modelers and also the Mendix Version Selector. When I went to install newest modeler it also re-downloaded the Mendix version selector. Fixed the issue. I no longer get that message when opening projects from the developer portal.
Hope that helps!