Please check your firmware version and type of firmware.
You can find the firmware version at the boot logo page(the first screen you see on the LCD).
There are two different model in NVS2525.
1) NVS2525 normal version
2) NVS2525 UDF special version
NVS2525 UDF special version does not support exFAT formatted memory card at all.
NVS2525 normal version does not accept UDF formatted memory card.
NVS2525 normal veriosn partly support exFAT formatted memory card, but if the file size inside memory card is larger than 4GB, it will not be supported.
If you added exFAT formatted CF card to NVS2525 UDF special version, you might see that error.
For further details, please send us the error code(number) you see on the LCD when you see the error.