Well when I originally had it on a breadboard I had the SD card running for 12 hour periods at a time from the Arduino Duemilanove and I've done that multiple times about 20 times. Never had a problem until I took it off the breadboard. Yes there is a pdf of the schematic of the board and uses for SD and SPI modes. I've had the jumpers on DIS, because of there connection to 3.3V.
There are voltage dividing resistors to drop the output voltage from the pins down to 3.3V on the pcb.
I've had a closer look at the pdf and I think I take back what I said.
I'd like to know how I had it working in the first place
The voltages on the breadboard were fine when first using the SD card slot and interface with the arduino.