I reckon that means that the floppy drive is electronically connected but not responding in the way the computer is expecting. I would check that the cable is the right way around. Second guess is that you've got the drive running in the wrong mode (this can be set in the bios)..** i am ignorant on this point so sorryif i'm talking bolx, but my understanding is that the japanese have a different standard called mode 3 which works in a slighty different way this can be set in the bios**
3rd option is that the drives knacked... have you got another you can try.... Check the cable first though (both ends!!) then check the right capacity drive is selected in the bios (ie, 1.44meg and not 2.88 meg that some bios allow you to select) then check the drive on another machine or put another drive in that machine.
Hope that helps