My Rockboxed Fuze "crash" when I start to transfer music from PC

[djfonplaz]

I have recently buy a SansaDisk Fuze V1. I have also put RockBox on it.

As first, when I connect to the PC, sometimes I see the window with somethings like "Device have some error. Do you want to analyse and correct them?".

I try correct them, and it says there are no errors (???).

Now, when I start to move files from pc to fuze, after some minuts the device looks like "it is not connected". The transfer fails, and I also cannot remove the device as "safe" (on Computer, if I click on the device, I open a empty folder). It looks like the DAP shutdown when is connected to my computer :O
I have windows professional 7 32bit.

Also, when the Fuze "crash", for start it I need to press the Power button for many seconds (4-5), I see a black text (somethings like loading firmware; it's too fast to read what is written. Is there an error log on Rockbox?) and then It start...
When is connected I say a USB photo and a text "USB Keypad Mode : Multimedia" (but this shouldnt matter)

I also see that, when I connect on PC, I see (on Computer) two new device : SANSA FUZE (I and another Removable Device (J (which I can't open)

What's happening? How can I solve this problems?