Says connected but isn't recognized

I am a happy user of a clip zip.
However, my computer stopped recognizing my clip zip.

It says “connected” when I plug in the usb, but there is no charging and it doesn’t get recognized by the computer.

I have used a different micro usb cable and I have the same problem

I am running snow leopard on a macbook pro.

Is the Zip’s USB connection mode set to MSC (Settings > System Settings > USB  Mode)? It must be in order to work with Macs.