I am one of them... Sadly I cant give a permanent fix to this.
I get the same Bglmanx.dll error when the game starts, then the sim crash when saying "Yes" to use it... I select "Restart FSX" in the Fatal error window, and the sim gives me again the same Bglmanx.dll, I said YES again and it will work... But something must be fix in the bglmanx.dll because we are many people with the same problem, others does not even know they can still play FSX with this problem... Just have to be patient.
How to use your FSX with Bglmanx.dll problem:
1-Start FSX (Run as administrator)
2-When Bglmanx.dll problem come to display,
answer YES. (As the picture shows)
http://i.imgur.com/QsjRUDt.png3-If your FSX crash before finish loading the main menu, answer
"Restart the program" (As the picture shows)
http://i.imgur.com/l8FXFfp.png?14-Then when the FSX is restarting, do the same... Answer Yes and it should send you to the main menu of FSX and you are ready to go!
I hope this help someone until FSDT can fix the Bglmanx.dll file or conflict that exist with it after the last addon manager update.
Cheers!
Mauricio Ravilet
Blainville, QC.