Thank you. /etc/apt/sources.list.d/ contained:

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

I then disabled the testing mode in Apps For Meego, uninstalled Apps for MeeGo alltogether and am now left with

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

This, of course, solves my problem with Apps For MeeGo.

Plus - surprise! - I was able to install all the applications from the Ovi Store that I had waiting in my queue.

Also, the ouptput of apt-get looks better now. The only thing that's still there is:

I wonder what this means.... It's irritating to have this on my phone.

Anyway, it seems getting rid of Apps for Meego solved the Ovi store problem, which in turn helped getting rid of at least one of the error messages in apt-get update.

Thank you very much!