Booting problem ubuntu second time

hii all,

I was sucessfull in installing ubuntu 10.10 in xM.....Now the problem
i m facing is that when i m shutting down the ubuntu and then again it
gives problem in rebooting .......so again i have to burn the image
into SD card and install the whole ubuntu again.....can anyone help
me?

And also anyone have any idea about the bug ....after this usb device
connected stops working

<6>[13862.106257] usb 2-1.1.1: USB disconnect, address 18
<6>[13862.353980] usb 2-1.1.1: new full speed USB device using
ehci_hcd and address 19
<6>[13862.463192] usb 2-1.1.1: configuration #1 chosen from 1 choice
<6>[13862.464401] generic-usb 0003:18EF:E015.0011: hiddev97,hidraw2:
USB HID v1.01 Device [ELV Elektronik AG FS20PCS] on usb-0000:00:1d.
7-1.1.1/input0
<3>[13862.501469] /build/buildd/linux-2.6.31/drivers/hid/usbhid/hid-
core.c: can't reset device, 0000:00:1d.7-1.1.1/input0, status -71
<3>[13862.533461] /build/buildd/linux-2.6.31/drivers/hid/usbhid/hid-
core.c: can't reset device, 0000:00:1d.7-1.1.1/input0, status -71
<3>[13862.565460] /build/buildd/linux-2.6.31/drivers/hid/usbhid/hid-
core.c: can't reset device, 0000:00:1d.7-1.1.1/input0, status -71
<3>[13862.597456] /build/buildd/linux-2.6.31/drivers/hid/usbhid/hid-
core.c: can't reset device, 0000:00:1d.7-1.1.1/input0, status -71
<6>[13862.618199] usb 2-1.1.1: USB disconnect, address 19
<6>[13862.850302] usb 2-1.1.1: new full speed USB device using
ehci_hcd and address 20
<6>[13862.961979] usb 2-1.1.1: configuration #1 chosen from 1 choice

Regards