unable to enumerate USB device on port 2

[OoZic]

hi
im new on this forum, sorry for my bad english, im italian.

i download backtrack 4 final iso, and then i create an usb live with unebootin.
i start the sistem, boot from usb, and start backtrack (1024*768), but there is a problem:
hub 4-0:1.0: unable to enumerate USB device on port 2
hub 4-0:1.0: unable to enumerate USB device on port 2
hub 4-0:1.0: unable to enumerate USB device on port 2
...

and so on... i can't do anything because this error loops.
what should i do?

the notebook im trying is an HP pavillion dv6000.

thanks for attention

[Archangel-Amael]

I don't know about the error but I have a dv6000 series and it works just fine. Both with a unetbootin stick and hdd install.
Try starting all over. md5sum correct etc.

[OoZic]

md5sum is ok

tomorrow i will try another time..
if it doesn't work what can i do?
other tips?

in the first boot screen, i have many options like:
default
backtrack (1024*768)
backtrack (800*600)
...

and so on, what should i choose?

thank you mate