Updating the addon manager in the running FSX always brings up the warning window (see attachment). I tried with and without msvcr71.dll being in the system32-folder.
What should I do about this problem?
That's not a problem of the Addon Manager installer, of course, which is just trying to do a proper installation of an outdated .DLL.
The "access denied", is caused by ANOTHER program which is currently running on your system, which use an OUTDATED version of the msvcr71.dll file. If the version wasn't outdated, the Addon Manager installer wouldn't even tried to update it, because it use the standard method to check for the .DLL version, not updating a file if it's not outdated.
So, your problem is caused by a combination of having the offending software still open, and this software is using an outdated version of the library.
In order to find the culprit, you should do the following:
- Restart Windows. Do not launch the installer yet.
- Close ALL the unnecessary programs that starts with Windows.
- Try to remove the msvcr71.dll from the Windows\System32 folder manually. If it doesn't give you an error, try reinstalling again.
If this still doesn't fix it, you can try this free utility here, which helps removing locked files:
http://www.iobit.com/en/iobit-unlocker.php
