What you are reporting is basically impossible to be happening so, either you are doing something else you are not saying, or what you said cannot just happen.
- If the QW757 is installed using the Flight1 installer, the airplane doesn't require and it's not affected by the Addon Manager anymore.
- On the Addon Manager page, were you say "there's only the FS9 version", there's also an alert which explains the lack of an FSX download link:
Since 2017, with the new Live Update system, the FSX/P3D version of the Stand-Alone Addon Manager is not required anymore, since the Live Update program can keep all FSDT products which are currently installed, always updated.
The date and time of the .dll in the FSX root directory matches the date and time when the live update was done so I know it's picking up the latest one from your live update.
Assuming you are referring to the bglmanx.dll, something is very wrong here, or you are doing something else, not just the Live Update. Since 2017, we DO NOT install anything in the FSX root directory, unless you explicitly said so ( which is not the default and it's not suggested ).
By default, all our installer installs into C:\Program Files (x86)\Addon Manager, or in any other folder you choose. Even if you chose the FSX root folder, the installer would have created an Addon Manager folder *UNDER* it, unless you manually corrected the final installation to force it into the FSX root folder. Is this what you did, which you are not saying ?
Because, installing into the FSX root folder shouldn't be done anymore, because that folder might be protected by Windows UAC and the updater might have an hard time updating files inside it. That's why we now install outside FSX, so the installer and the updater can have full access to a folder they have created, without having to worry about Windows file protections.
- Uninstall ALL your FSDT products.
- Reply YES to the question "Do you want to remove the Addon Manager ?". This will allow you to choose the install destination again.
- Reinstall all your FSDT products, using all the current installers. DO NOT change the default folder. C:\Program Files (x86)\Addon Manager is entirely fine, and the only reason you might have to install elsewhere, is if you don't have enough space on C: If this is the case, just select the root of any drive, like D: or E: or F: which will result in all our FSDT product ending under D:\Addon Manager, E:\Addon Manager, etc.