I posted this at ASN and it stumped Damian (he asked that I open a ticket), so I thought someone here might have an idea of what could have gone wrong:

 

I installed ASN SP2 with my FSX:MS install and now ATC menu commands are ignored completely, e.g. when I select to request taxi to runway nothing at all happens, though I can switch to different ATC menus without problem. I uninstalled ASN and reinstalled with SP1B and the ATC commands came back. I then reinstalled SP2 with the same results as the first time. Any suggestions?

 

Thanks for reading.

Is the ATC menue also not active if you use the mouse for clicking the radio commands or is it only when using keys? First thing I was thinking about was: the keys used for communication are mapped to something in ASN after the installation of the update. Second thought: I once had the problem that my radios were off even though they seemed to be on. Do you observe the mentioned phenomenon in all planes? If both do not apply for you, I sadly have no idea as I do not own ASN...

Fixed my problem. Here's what I did:

In FSX.cfg I deleted the entire contents of the [trusted] section, and then deleted exe.xml (well not really, just renamed it).

Upon restart of FSX, all ATC menu operations worked perfectly.