I had pretty much the same problem, what I did was backing up and removing all sources from /etc/apt/sources.list.d/ except these two:

aegis.ssu-keyring-001.list
osa.list

After a reboot the store worked fine.
Don't know which of the other sources caused the ovi store to not work, but if I were you I re-add the sources one by one - as soon as the store is working again.