Because FLAC is freeware it comes in a lot of different flavors. Some versions might take extra processing power from the Fuze–which, remember, does not have the resources of your laptop.You could try converting it to a newer or older version.
64-bit FLAC is not supported by SanDIsk. I don’t know if Rockbox has figured out a way to play it.
The other variable might, conceivably, be the class of the card, which governs how fast the processor communicates with the memory. One poster had a class 2 card, the slowest. My 8GB and 16GB class 2 cards work fine, but I haven’t tried a 32GB.
