Refreshing your media problem usually means there is something in your media that the Sansa is choking on.
It might be some glitch in the database, the index of your files. You can try deleting MTABLE.SYS in the Fuze drive. That’s the database. After you delete it, the Fuze will reconstruct it from scratch as it reboots–that’s what it’s refreshing–and your problem may disappear.
Or it may not. There may be an ID3 tag on one or more of your files that the Fuze is choking on. It’s not as flexible as the much bigger brain of your computer. Personally I doubt any firmware update will ever fix the problem completely.
If ID3 tags are the problem, your best move would be to make sure you have copies of anything you have put on the Fuze and then format it under Settings/System Settings. That erases everything you put on. Then load it back on, little by little, until the Sansa chokes again, take off your most recent addition, and try again. (Possibly erasing MTABLE.SYS again.)