Difficulties with Custom POIs and the 3790LMT

My nuvi 660's speaker decided to imitate tissue paper wrapped over a hair comb and is difficult to understand. My wife and kids bought the 3790LMT for Father's Day (although my wife has used it every day in her exhausting commute).

I wanted to transfer my many POIs gathered from POI Factory onto the new nuvi. The first thing I did was register the new unit with Garmin and I was advised to upgrade my version of POI Loader (Windows Vista machine). In reading through some posts, this seems to have been the first mistake since some folks are reporting that the latest version is intolerant to file issues that the previous version dealt with.

With the latest version of POI Loader, I chose the nuvi 3790 as the device to transfer the POIs to and then began the process. Every single time I attempted, the program stopped. Each and every time it displays:
Reading data files...
82% complete and 6 seconds remaining.

After much frustration, I simply created a new folder on the computer and transfered just the red light file, bitmap and .wav . The nuvi took this and these POIs worked just as expected (minus the known absence of any visible .bmp).

I had hoped that the program balked because the nuvi lacked sufficient memory to load all of the POIs.
I ordered an 8GB micro SD HC Class 4 card. It arrived today and I inserted it into the nuvi. The nuvi made no indication or acknowledgment of the memory card being added, but when I hooked up the nuvi to the computer the card was recognized.

I quickly updated the POIs that were refreshed in the "My Favorite Files" list and then ran POI Loader again. This time I picked the removable media from the drop down media (drive H:) which was inserted into the nuvi. Just the same- stuck at 82% and 6 seconds remaining.

I decided to just load the Red Light poi files into the micro SD card inserted into the nuvi and that went well- just as it did when I loaded them directly into the nuvi memory.

When I turned on the unit and chose "Extras" the nuvi indicated that no custom POIs were loaded. The nuvi did not recognize them on the memory card that was installed. I double checked and they were properly transfered.

In order to at least keep the Red Light camera info available, I had to reload them into the nuvi's native memory.

The Owners Manual for the nuvi offers a few sentences about a memory card and does not even indicate what specs would be recommended. I did know this information from looking elsewhere on the internet.

-So, I now have an up to date version of POI Loader that will not work well with the identical files that a former version of the software did (and no way on Garmin's site to revert to the older version- which I hope woudl even be compatible with the 3700 line).

-I have an installed memory card in which POIs installed are not seen by the nuvi.

And beyond a screen that offers no additional data beyond 82% and 6 seconds remaining, I have no way of knowing which POI file out of the many dozens I have loaded may be offensive to the newest version of POI Loader.

Can anyone shed some light or offer any suggestions?

Thanks!

Rob - Long Beach, NY