keyboard works in BIOS & GRUB but not during boot

[scar]

i just installed ubuntu 10.04 alongside a machine with windows xp on it,
and the installation went well.  i resized the windows partition and
installed ubuntu to an encrypted partition.  the keyboard works in BIOS
and in GRUB, but, after that, when it is booting and asking me for the
passphrase to unlock the drive, i cannot enter it.  also the num lock
doesn't turn on/off at this point either.  i'm just using a run of the
mill USB keyboard and mouse.  the keyboard/mouse work fine when i boot
into windows also.