Building a usb-hdd after iso fails to create binary.img

["John E. Conlon" <jconlon@verticon.com>]

Am building iso and usb-hdd images.

Can build the iso, but if I then try to build a usb-hdd (using -b 
usb-hdd), even after I do a lh_clean --binary ( have also tried 
combinations of lh_clean with --purge && --cache) the build does not 
create a binary.img.

Here is my lh_config
lh_config -b usb-hdd --hostname tracker1 --username irouter 
--iso-application "Product A" --packages "openjdk-6-jre-headless ssh" 
--iso-preparer "Verticon, Inc. ; http://verticon.com"; --iso-publisher 
"Verticon, Inc.; http://www.verticon.com"; --syslinux-timeout 5 
--bootappend-live "persistent ip=frommedia"

At the end of my build I see the following:

0+1 records in
0+1 records out
404 bytes (404 B) copied, 8.7092e-05 s, 4.6 MB/s
loop: can't delete device /dev/loop0: Device or resource busy
P: Begin unmounting filesystems...


Any tips of what else I should look for in the log of the build to 
resolve this issue? 

BTW - I had this working a couple of weeks ago, but now don't know what 
I may have hosed up.  Also I can build a usb-hdd in a fresh directory 
with all the defaults. 

thanks for any help,
John