you don't seem to understand the ide referencing method..
hdc is a reference to the physical device, A harddrive, a cdrom drive, and ls120 disk drive etc... hdc1 is a partition upon a harddrive. so you DO have hdc.
hdparm works up a device, and not a partition, operations of DMA or PIO modes operates outside the scope of partitions.
just try 'hdparm /dev/hdc' to start off with, IF that's going to help at all.