Standalone CTD (Access Violation) - Making sense of "error.log" files?

While testing a standalone windows build on a machine inferior to the one used to develop the game, I experienced several Crashes-To-Desktop. I found "error.log" files created by the crash events, but I'm still entirely in the dark as to the root cause.

The game has yet to crash on my newish development machine, but the game's nature is simplistic enough that I expected the inferior machine's specs to be more than adequate.

Besides injecting Debug.Log statements all willy nilly, or installing Unity on the inferior machine and testing with the profiler, what can I do to help identify the source of this crash? Exactly what does this error.log tell me about the problem?

Big thanks for any insight.

Bonus Question: Are we expected to install Unity on every test machine to get access to tools to help us identify problems? How else but by experimentation can we anticipate a game's minimum system requirements?

MAR19.exe caused an Access Violation (0xc0000005)
in module MAR19.exe at 001b:017576dc.

Error occurred at 2015-03-29_195622.
C:\Users...etc...\MAR19.exe, run by Unknown.
75% memory in use.
3455 MB physical memory [856 MB free].
0 MB paging file [1155 MB free].
2048 MB user address space [18 MB free].
Write to location 00000000 caused an access violation.