I have never moved the sim so registry should point to sim location, and the installer finds it ok after I enter the install location
This is already strange: our installer will NEVER ask for the place where the simulator is installed, because it will find it automatically ( looking in the registry ) or it will not find it, and if it's not found, the simulator entry for the sim that hasn't been found will be greyed out.
I think you are confusing what the installer is asking you when you "enter the install location". It's NOT asking for you to tell where the simulator is, is asking where you want to install THE ADDON MANAGER, which will be a shared location for all FSDT products. By default it's C:\Program Files\Addon Manager but, it can be any other folder and usually the worst possible choice is precisely the folder the simulator is installed into, because if you install it there, there *might* be some file permissions problems that might prevent something from working correctly and, in general, with P3D4/5 is a very bad practice to install things "inside" the simulator, and we took great care to not to do that so, choose any folder you like EXCEPT the simulator one, because that's not what the installer is asking for.
Then about midway through the install I get the error PROBLEM ACCESSING XML FILE - AN ERROR OCCURED WHILE PARSING ENTITY NAME, LINE 6, POSITION 21
Please be more precise on when this happens, exactly. During the actual installation, or after the FSDT Live Update starts ? This usually means either your DLL.XML or your EXE.XML file were already corrupted but the thing is, we don't use them in P3D4 or 5, only in FSX.
