Is it possible that I may need a more recent version of VC++ runtimes installed?
Ideally, you need the same version we used to link our software with, which we obviously install when running our installers, and it's exactly the same as the one supplied with FSX SP2 so, on a correctly installed system, it's always supposed to work.
But, if you already have a more recent version, the older one will not be installed, and even if the newer versions are forward compatible, if you have a *problem* with them, programs using any version of the 2005 runtimes will not start.
Which is why sometimes is best to remove everything and start from scratch again. There are known issues of a specific 2008 version which broke the 2005 version, that's why I've suggested to remove both and reinstall both, and then run a Windows Update.
VC++ Runtimes in Windows Update are not always obvious: they are often presented as "security hotfixes", which silently upgrade the runtimes so, even if you don't see anything which *seems* relevant to them in Windows Update, do all the updates anyway.