Iomeg 2.0 not mounting

[Jayman]

I have a g5 dual processor with an external Iomega which sometimes mount and sometimes does not...have contacted apple care...had me re-set everything and still the error medssage..."you have inserted a disc which Mac os cannot read....but then after plugging the usb cable ( have also tried firewire) in and out and turning the drive on and off...bingo..and yes it has been formmated, otherwise I cound not save 44gisg of material..any ideas.?.tx