By default, the vfat filesystem will try to use the native language
charset iso8859-1 for doing conversions from/to Unicode. If it is
unable to load it, it will continue to work, but it will fall back
to no conversion. If compiled as a module, the module filename would be
fs/nls_iso8859-1.o. If compiled into the kernel, you should never see
this message. I suspect that you've neither compiled it into the kernel
nor as a module. You don't need to use the NLS modules for things to
work as they have in the past. The NLS modules become more helpful
when dealing with Unicode characters in vfat and Joliet.
- Gordon