Just a tip for people who cannot get POIs working on Garmin mobile XT. If you are running Garmin on a microSD card try putting POI's on the phones main memory with POI loader. For some reason it is the only way it will work on my phone.
I've found the same. It feels better to put the big files on your external microSD, but for some reason it doesn't always mount correctly. In your phone's inbuilt memory, I've never had a problem.