Cache is NOT at the posted coordinates
You will find the cache at the following coordinates:
Abegu Guvegl Rvtug Qrterrf Guvegl Avar cbvag Frira Uhaqerq naq Friragl Svir Jrfg Bar Uhaqerq Gjragl Bar Qrterrf Gjragl Avar cbvag Mreb Friragl Sbhe
Once you find the cache place your autograph on the log before returning the container right back where you found it.
Your really shouldn't need a checker but one is provided.
You can validate your puzzle solution with certitude.