Use a text editor to open your FSX.CFG file located at
%APPDATA%\Microsoft\FSX
find the [Trusted] section there, and remove all the lines that contains bglmanx.dll inside, remove the whole line including all the extra characters.
Save the file, on the next FSX launch it will ask again to run the Addon Manager. If you blocked the Couatl Scripting Engine, you should do the same for Couatl.exe