Trying to use the sample code in starterware to write to a USB drive

I've been playing around with the USB code that ships with the starterware for the LCDKC6748. I've got it running and can properly read a file from the USB key. There is no write command so I tooke the read (cat) command code and modified it to write to a file. The fat-fs function f_open works and returns the proper status when I open a file for writing and the f_write finction seems to return OK. When I call f_sync or f_close I get an error and no data is written to the USB key. Does the low level code that ships with the example work properly? Has anyone got it writing to a USB key? Sorry if this is the wrong form, if so just let me know the proper one and I'll post my question there.

Thanks,

Blair