Yes Jumpers, though, I don't know what the dip-switches do so I wouldn't rule that out either. I don't know if you have a manual, maybe there is some info in it?jumpers, not these dipswitch right?
the only info I can find related to Chihiro jumpers is for DIMM and Netbooting:
1 - ?
2- ?
3- ?
4- ?
5 - 1-2:1GB DIMM | 2-3:512MB DIMM
6- ?
7- ?
8 - 2-3

9 - 1-2:GD-ROM | 2-3:Network
10 - 1-2

Maybe @winteriscoming can confirm his jumpers or any other info related to card readers since he's done a lot of work with these.
EDIT: I just had another thought, are you using compatible card readers? if the card readers you're using aren't designed for your specific version of WMMT they may not work.