"EXE Path" is a string value and not a key. So you will find it on the right side of the registry editor. If you don't have it, you will need to create it and enter you path to the main FS folder. Then it should work.
You need to download the latest TTools version from AVSIM.com and unpack the archive to the subfolder "TTools" in the main AITM folder.
Hope this helps