I recently had a problem with PMDGsounds.dll and searched AVSIM for a solution. There are quite a few threads asking for help with no replies. There are also a couple of threads which had solutions which didn't fix my problem. When I eventually fixed things I thought it was worth adding my solution to the forum in case someone else has the same issue in the form I got it.

 

The warning first came up after I'd been flying the MD-11 and then shutdown FSX to restart it and fly the 777. I got a large pop-up error window reporting a problem loading PMDGsounds.dll. It offers you the option to try loading it anyway (YES) or not (NO). I tried choosing YES but got a CTD. I assumed the DLL had got corrupted when I shutdown FSX, so uninstallled the MD-11 and reinstalled it to get a fresh copy of the DLL. FSX loading still came up with the same error. I then tried choosing not to load PMDGsounds.dll in the error window and this time FSX loaded OK so I loaded a flight as well. There was a red error message about sound drivers in a green bannner across the top of the screen. I opened the Windows Device Manager and noticed the sound controller was missing. Bingo! So I closed FSX and reinstalled the sound drivers from CD-ROM. The sound controller was back in the Device Manager and the sound driver error message in FSX was gone.

 

So my problem hadn't been with PMDGsounds.dll itself but the corrupted sound drivers it needed to use. Now all I had to get FSX to load with PMDGsounds.dll. I still got the same dll loading error message but I chose to load PMDGsounds.dll anyway and it ran successfully. Problem solved.

 

So this error can mean PMDGsounds.dll is corrupted, but it can also mean the PC sound drivers themselves are corrupted.

Yeah this error is almost always the result of some out of the norm sound configuration on the machine. Stuff like no speakers at all, a USB headset that is unplugged, selecting crazy surround modes that didn't exist when the product was programmed, etc.