Geocaching Mystery

So, my grandson, Kelton and I headed out to do some geocaching on a very dreary, wet winter day. We had great fun, found two caches, but ran into a bit of a mystery with one of them. If you're a geocacher and can shed some light on this, please let me know.

Here's the deal: I went to geocaching.com with my brand new Garmin Nuvi 500 attached to my MacBook Pro. Found this cache (GC17B78) and clicked the "Send To GPS" link. No problem. But every time I opened the cache on the Nuvi, the device turned off! I thought maybe the GPX file was corrupt somehow, so I overwrote it several times. But it still didn't work. The Nuvi works fine on all the others and we've had no trouble with it at all. It's just this particular cache. Has anyone ever encountered this? Any clue what might be going on?

We ended up just printing the page and walking until we were at the coordinates. It's an easy cache and loaded with lots of good stuff. Sadly, the fish hatchery is covered with mud right now because of recent flooding, but no fish were lost. We look forward to going back when the weather's nice and the mud is gone.