There is nothing hidden at the posted coordinates. You will need to solve the puzzle below in order to get the coordinates to the actual cache. This cache is being placed in honor of the Tri-State Geocachers' annual Geo Tech U event, at which I'll be presenting.
According to wikipedia, the Latin phrase "omne trium perfectum" means "everything that comes in threes is perfect," or, "every set of three is complete" and it conveys the same idea as "the rule of three," which is a writing principle that suggests that things that come in threes are funnier, more satisfying, or more effective than other numbers of things. I knew there was a reason that the Tri-State Geocachers of PA/NY/NJ are such a special group! It seems only fitting that this puzzle has three parts, each of which incorporates the theme of the number three in some way.
To get you started, I suggest you consult this web page where you will find information about the cipher I chose for the first portion of the puzzle. It's called a Tri-Square cipher, which seemed perfect for the occasion. The setup of the keysquares is the same as in the example from the web page, with the following important changes: I omitted the letter Q instead of the letter J, and I chose my own key words. I bet with a little thought anyone from the Tri-STATE area can figure out what three words I chose and which one goes in which square. Decode the cipher and then follow the instructions to find the cache.
YNK JHP PSA WWB ZZB SCM RAD EIV UJI BHK ZJW KXW ZEN MBP VIZ UJD VHC WJW CLO HHB SLN EVI OBY KYP UXO AEM NUH LUD FVJ NSM PVP PLY BLO IEN YAL
A big thanks to RedKnight for agreeing to maintain this cache for me!