Just got an e-mail ftom the MA Wherigo GC19THA cache owner saying that the issues with cache and the 400t have been resolved. I have downloaded the revised cartridge and it seems to be working properly now. We will try to get to the cache this week and will report our adventure. There are sixteen finds of the cache now, but they have all been done with a PPC and not a 400t, as far as I can tell.