FatFS f_write returning FR_DISK_ERR?

I am trying to use FreeRTOS and the FatFS library (inside the TivaWare third_party). However I keep getting a FR_DISK_ERR when i try to use f_write.

The function I am using is like this: basically it will pen the file and then try to write to it. I do not execute another task in between and the initTivaForSDC() reconfigures to pins. If I run a directory list, it lists all the files available, this suggests that it is still talking to the SD card.

void placeInQueue(VehicleData value, FileStruct* fStruct, char* name)
{
	TCHAR message[SD_MESSAGE_LENGTH]; // 30
	UINT bw;

	initTivaForSDC();
	if (fStruct->fileInstruction == FILE_CREATE)
		{
			if (! fStruct->fileOpen)
				{
					iFResult = f_open(&g_sFileObject, fStruct->fileName, FA_WRITE | FA_OPEN_ALWAYS);
					fStruct->fileOpen = true;

					if(iFResult != FR_OK)
						{
							UARTprintf("Error Opening file: %s\nError: %s\n", fStruct->fileName,
							           StringFromFResult(iFResult));
						}
					else
						{
							UARTprintf("Successfully opened %s\n", fStruct->fileName);
						}

					usnprintf(message, SD_MESSAGE_LENGTH, "%u,%u,%u\n", 0, 1000, 50);
				}
			else
				{
					// Things went ok
					usnprintf(message, SD_MESSAGE_LENGTH, "%u,%u,%u,%u,%u\n", value.timeStamp,
					          value.speed,
					          value.odom, value.forAccel, value.latAccel);
				}

			UARTprintf("Attempting to write %s\t", message);
			iFResult = f_write(&g_sFileObject, message, SD_MESSAGE_LENGTH, &bw);
			if(iFResult != FR_OK)
				{
					UARTprintf("Wrote: %u\tError writing to file: %s\n", bw, StringFromFResult(iFResult));
				}
			else
				{
					UARTprintf("Wrote:\t%s\n", message);
				}

			iFResult = f_sync(&g_sFileObject);

			if(iFResult != FR_OK)
				{
					UARTprintf("Error syncing to file: %s\n", StringFromFResult(iFResult));
				}
			else
				{
					UARTprintf("Synced:\t%s\n", fStruct->fileName);
				}
		}
	else if (fStruct->fileInstruction == FILE_CLOSE)
		{
			iFResult = f_close(&g_sFileObject);

			if(iFResult != FR_OK)
				{
					UARTprintf("Error Stopping write to file: %s\nError: %s\n", fStruct->fileName,
					           StringFromFResult(iFResult));
				}
			else
				{
					UARTprintf("Successfully Stopped %s\n", fStruct->fileName);
				}
		}
	if(xQueueSendToFront(g_pDataQueue, &value, 0) != pdPASS)
		{
			char errorString[10];
			usnprintf(errorString, 10, "xQS %s", name);
			//
			// Error. The queue should never be full. If so print the
			// error message on UART and wait for ever.
			//
			UARTprintf("%s Queue full. This should never happen.\n", name);
			errorScreen(errorString);
		}
}

And the following is printed:

STARTING to Write to file: 1000-kg_500-mm_0.txt
Successfully opened 1000-kg_500-mm_0.txt
Attempting to write 0,1000,50
        Wrote: 0        Error writing to file: FR_DISK_ERR
Synced: 1000-kg_500-mm_0.txt

Any tips would be greatly appreciated!