[Conspiracy Theory]
What brand drive is in all of your players? I am going to bet all of them are Fujitsu. I had the same problems with my 60GB Fujitsu player. I replaced the Fujitsus with IBMs (same cable) and haven't had this problem since.
[/Conspiracy Theory]

Lucky for me, I was able to use the Fujitsu drives in other things. So, replacing them wasn't a total loss.