[Pyusb-users] device or resource busy

[<dai...@al...>]

hello,
while running this program (from the README file, into the package =
pyusb-0.3.5)..

#____program____


import usb                 # import the usb module



bus =3D usb.busses()         # get a list of all available busses



dev =3D bus[4].devices[0]    # choose the first device on the first bus



handle =3D dev.open()        # open the device



for alt in dev.configurations[0].interfaces[0]:

    print alt              # look at the alternate settings.



handle.setConfiguration(0) # choose the first configuration



handle.claimInterface(0)   # choose the first interface



### Use the device here. ###



handle.releaseInterface()  # also called automatically on __del__



#____end____

..i got the following error:

Traceback (most recent call last):
  File "progreadme.py", line 13, in ?
    handle.setConfiguration(0) # choose the first configuration
usb.USBError: could not set config 0: Device or resource busy

every bus number i fill in, i got the error, and if i comment the error =
line, error in the next line: still "device or resource busy".
i have to run it as a Super User, or i'm told "operation not permitted", =
but i think that's normal.
can someone help me?
i'm using debian 4.0 etch
 thank you -and sorry for my bad english-
  stefano