Dell OptiPlex 210L halt at boot

Hi list,

 I'm trying to install FreeBSD on a Dell OptiPlex 210L and the machine halt
at boot.
 I tried with 6.1, 6.2, 7 and all halt at same point follow the last line
before boot halt:

usb1: host controller halted

on FreeBSD 7 the following lines appeared after:

panic: usb_insert_transfer
cpuid = 0
kdb: enter: panic
[thread pid 0 tid 0]
stopped at kdb_enter+0x02b: nop
db>

This machine does not have ps2 port, the keyboard is usb, so I can't do a
"bt".

I can do more tests to track down the problem, just explain me how to do
that.

 Regards,

Alexandre Biancalana