The spinning arrows thing is an indicator that the Reader is parsing the contents of the card (which can take it a while with almost a Gig of stuff to sort through). The spontaneous reset is probably where you need to focus.
The way I'd try to stop it is to hit the reset button (the pinhole on the back that's marked "Reset,"
not the little hole by the power switch
), remove the card, and then restart the device by exercising the power switch.
Then I'd take a look at the card. I think I'd start with moving everything off it and seeing if the Reader has an issue with just the blank card. Maybe even try re-formatting it, just to get a clean slate.
Then just play around with it, move some files back and see what it does with them.
If you want to be all methodical about it and stuff, you could test your file set to make sure it's not an individual bum file, by removing half of them and seeing if the problem recurs. If not, go back to the other half, if so remove half of the remaining files. Repeating that will get you down to a problem file, if there is one, pretty quickly, even though the Reader is pokey about parsing them.
Hopefully that will get you started, at least ....