Digital BW, The Print

I got a c88+ fairly cheap to try the MIS EZ inksets on, and am having trouble getting them to 
work in my printer. I load the cartridges in just like any other, and the printer won't print, 
telling me to replace the yellow cartridge. It works fine with a yellow epson cartridge, so I 
figure there is something wrong with the MIS cartridge.
 Any tricks I should try?