Cache is NOT at the POSTED coordinates.
To find the cache, solve the following puzzle:
56 52 72 36 62 64 52 72 36 57 64 52 51 72
64 24 71 42 56 24 56 42 74 52 24 56 36
64 24 71 42 64 52 51 72 34 24 55
27 42 34 36 53 42 72 52 56 24 56 42
36 62 72 42 42 36 27 52 34 24 55
46 52 36 53 42 72 52 34 24 55
42 24 66 62 36
You can validate your puzzle solution with certitude.
Frireny jnlf gb fbyir. Chmmyr: 1) nantenz gvgyr jbeqf. 2) vzntr