Appx - 41440:  appx.exe - application error

  The instruction at 0x004992b0 referenced memory at 0x004992b0.   
  The required data was not placed into memory because of an 
  I/O error status of 0xc000020c.

There were most likely occasional, brief network problems when trying to load a block of appx.exe executable into his client PC. This can happen after initial appx.exe -c program loading, because the OS grabs 2k blocks of the disk form of the executable, as needed. (The problem can also be a disk fark, or a controller error.)

The solution is to bring the appx.exe previously stored on the network server down to the local PC hard drive, to eliminate this potential network problem.