100 mb internal zip mpc2000xl

I installed the internal 100 mb zip and it recognizes it as atapi but wont read disks. I press format, load, and this pops up(DISK READ ERROR). I am using 100 mb mac formatted Iomega disks, is this the problem or is the drive not working properly. Also, I'm not for sure which OS im running on, How do you find out?

thanks,

Chris[/u]