fat_AutoMount() failed with return code -38

I have kit RCM5450W. When I Mount EEPROM with function fat_AutoMount() his return value is -38. This value is’nt specified in datasheet.
Example code is here:

temp = fat_AutoMount(FDDF_USE_DEFAULT);

first_part = NULL;
for (i = 0; i < num_fat_devices * FAT_MAX_PARTITIONS; ++i) {
if ((first_part = fat_part_mounted[i]) != NULL) {
break;
}
}

if (first_part == NULL) {
	temp = (temp &lt; 0) ? temp : -ENOPART;
} else {
	printf("FAT was succeeded mount

");
temp = 0;
}

if (temp &lt; 0) {
if (temp == -EUNFORMAT)
  	printf("Device not Formatted, Please run Fmt_Device.c

");
else if(temp == -EBADPART)
printf("FAT failed! Partition is not a valid FAT partition
");
else if(temp == -EIO)
printf("FAT failed! Device I/O error
");
else if(temp == -EINVAL)
printf("FAT failed! Invalid prtTable
");
else if(temp == -ENOPART)
printf("FAT failed! No partitions exist on the device
");
else if(temp == -EBUSY)
printf("FAT failed! For non-blocking mode only, the device is busy
");

  exit(1);

}

Where is the problem???

Thank you very much!