What is Exception Code 0xc0000005? On Google there are hundreds of reasons for this fault.
It's the most generic error you can imagine, an access violation, which is an attempt to write in a memory area that you are not supposed to access. This is usually caused by a program that is trying to parse files and find something unexpected, such a file that don't conform to its standard file format, or simply a corrupted file.
What is Couatl.exe trying to access immediately after the start of FSX? If I knew that I could perhaps look further.
The AFCADs for all your sceneries active in the Scenery Library, in order to build a cache of them, that will allow it to access the needed file faster in case you use that airport. The cache rebuild is done only when you add/remove a scenery OR (and this is your case) if the previous startup, the cache couldn't be rebuilt entirely (due to the program crashes)
FSX is running on Drive D:\. However, The Program Data folder is on Drive C:\. Is this correct?
That's not a problem. I'm fairly sure the problem must be one of your AFCADs which is either corrupted or not entirely standard.