card reader not reading SD

Bought an SD card at wal-mart, put it in my computer and loaded samples. But when I put it in my card reader on the MPC it says "not ready!". I figured this could be a problem. I also got samples on my CF card, but when I load it to the MPC the bottom portion of the screen says a bunch of question marks. What could this mean?

To make the card readable for the pc and mpc as well,you have to run the 1.2 operating system on the mpc and format your card in the machine before you put the card into the reader on your pc.Basically when you format card under 1.2 OS it makes 'her' visible for the pc drive.
You can find the answer for second question in the manual.I suppose that question mark means unknown file type.Make sure taht your samples are 16 bit,44 kHz.
By the way Compact Flash cards work better than SD - less problems.

thanks for your response