From what I saw yesterday, SimConnect needs to be working on both computers.
Supposedly, each version of SimConnect is compatible with the versions below it.
FSX, FSX:SE, and all versions of Prepar3d can work with the multiple versions of SimConnect concurrently.
This download link http://forum.aerosoft.com/applications/ ... p?id=67233 contains a zip with all three versions of SimConnect. (Black Screen and Side Stick not working)
I don't see where it could hurt to install all three versions on both computers.
Then run the SimConnect test on each computer.
Another possible source of problems.
A few years ago I had a Plan-G problem due to a corrupted .NET Framework.
Take a glance through this post - Plan-G 2 & 3 dead.
.NET Framework is used in a great many programs. My version of .NET Framework was only partially broken which made it harder to track down.
Two resources are;
1) - How to uninstall Microsoft.net framework 4 client profile Read the post marked (check mark) Answer. See link http://cid-27e6a35d1a492af7.skydrive.li ... p_tool.zip
or
2) - Automated cleanup tool to remove the .NET Framework 1.0, 1.1, 2.0, 3.0 and 3.5
If you doubt your computer capabilities, you may want to skip all that. That it worked for me, is all that I can say.