USB 2.0 transfer doesn't work with my 8GB Sansa FUZE

Hi:

Today I connect my sansa to my wall charger to charge it and then try to pass music but got the blessed message “Your device coule be work better on USB 2.0 Port …” i dont take care importance , then try plugging in another computer but same thing happened.Since the format and reinstall the latest update.I have a 8GB Sansa Fuze  Revision 1.
Someone knows the solution to this problem?

Thank you.

My 8GB Sansa Fuze is not compatible with my USB 2.0,what I did is I brought another one that is compatible with it. :cry: