Bootloader install FAILS when USB install disc is SDA and HD is SDB

I can't successfully install from a USB install media. I get to the end and when it tries to install GRUB it complains that there was a fatal error writing to SDA which is my USB drive. I told it in the install that I wanted it to install to SDB (both using the standard disk menu and the manual one).
It lets me choose a place to try and install grub - so I choose both SDB and SDB1 and no luck. It says I am fine but when I reboot there is no bootloader so the machine never boots into Ubuntu.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: ubiquity 2.8.7
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
ApportVersion: 1.23-0ubuntu3
Architecture: amd64
CasperVersion: 1.287
Date: Thu Nov 17 18:22:04 2011
LiveMediaBuild: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)