suddently seeing "W: Release file did not contain checksum information" errors...

For a home-grown apt repository which had been previously working for
eons, I'm suddently seeing

W: Release file did not contain checksum information...
W: You may want to run apt-get update to correct these problems

errors, when trying to issue 'apt-get update' against it.  Re-running
genbasedir or 'apt-get update' doesn't (seem to) help.

I'm puzzled mostly because the error seems *wrong* (the release file
*does* contain correct checksum information).  A concrete example on my
RedHat EL4 box:
$ apt-get -version
apt 0.5.15cnc7 for linux i386 compiled on Apr 11 2005 14:33:46
Supported Modules:
*Ver: Standard .rpm
*Pkg:  rpm interface (Priority 20)
  S.L: 'rpm' Standard RPM binary tree
  S.L: 'rpm-src' Standard RPM source tree
  S.L: 'rpm-dir' Local RPM directory tree
  S.L: 'rpm-src-dir' Local SRPM directory tree
  Idx: RPM Source Index
  Idx: RPM Package Index
  Idx: RPM Database

$ apt-get -q update
...
W: Release file did not contain checksum information for
file:/linux/kde-redhat/redhat/4/i386/base/pkglist.stable
W: Release file did not contain checksum information for
file:/linux/kde-redhat/redhat/4/i386/base/release.stable
...

$ grep release.stable /linux/kde-redhat/redhat/4/i386/base/release
  d86fd72961c348de7e3b4acc141f8859 158 base/release.stable

$ md5sum /linux/kde-redhat/redhat/4/i386/base/release.stable
d86fd72961c348de7e3b4acc141f8859  release.stable


Any ideas?

-- Rex