Apt keeps giving me "400 Bad Request"

[Pete Harlan <harlan@pointofchoice.com>]

I'm upgrading slink->potato.  Each time I run 'apt-get dist-upgrade'
(after having initialy run 'apt-get update') it tries and fails to
grab a number of packages before giving up; each one looks like this:

-------------------------------------------------------------------------
Need to get 109MB/140MB of archives. After unpacking 51.9MB will be used.
Do you want to continue? [Y/n] 
Get:1 http://http.us.debian.org potato/main libtiff3g 3.4beta037-8 [77.2kB]
Err http://http.us.debian.org potato/main freetype2 1.2-6.1                    
  400 Bad request
Get:2 http://http.us.debian.org potato/main eterm 0.8.9-9 [467kB]              
Err http://http.us.debian.org potato/main imlib-progs 1.9.7-2                  
  400 Bad request
-------------------------------------------------------------------------

My sources.list looks like

deb http://http.us.debian.org/debian potato main contrib non-free
deb http://non-us.debian.org/debian-non-US stable non-US

Each run of apt-get does make about 5mb of progress.

Intel, 28.8 modem link, plenty of disk space/ram, etc.

What dumb thing am I doing wrong?

Thanks in advance,

--
Pete Harlan
harlan@pointofchoice.com