You guys are gold - the signature errors are gone!

after some successful updating, apt-get update still produces a couple of lines like these though:
N: Skipping acquire of configured file 'main/binary-armel/Packages' as repository 'https://maedevu.maemo.org/leste chimaera-devel InRelease' doesn't support architecture 'armel'

How does this armel stuff get in there...?