I ran filemon while starting the sim, and the problem does seem to revolve around bglman.dll
Your test only indicates that the FS9.EXE process is reading from bglman.dll, which is quite normal, since it's bglman.dll it's an FS9 plugin that is being loaded by FS9 so, obviously FS9 will read it at some stage.
Your test doesn't indicate the problem with FSUIPC has any relationship whatsoever with bglman.dll
A system restore seems to be the only way to get the sim back. The problem surfaced after installing/uninstalling KLAX.
The problem is not caused by the Addon Manager or KLAX, and the proof is EXACTLY that FSUIPC message.
Since, as I've said already, the Addon Manager doesn't install, don't come with, doesn't use, doesn't call, doesn't need and it's not affected or related in ANY way to FSUIPC, the simple explanation is that you have ANOTHER problem, with is affecting BOTH the Addon Manager AND FSUIPC, which are both "victims" of the problem, and none of them is the cause.
Could you just remove the bglman.dll file from the MODULES folder, and see if you still have the FSUIPC error ?