The cache IS at the posted coordinates. This is a challenge cache.
The Challenge
This challenge really is Easy Peasy.
In order to log a find, you must have at least 100 caches. Yes, that's it!
The Rules
Once you have signed the logbook and the Project-GC checker confirms you have completed the challenge you can log it as Found. Until then you may post a note if you have only signed the logbook.