Tried that.
Same error appeared afer trying to reinstall mappero
Now neither mappero or extra decoders (uninstalled as suggested above) will install.
Never had Mirror installed - which is suggested may also be to blame.
On attempting installation:
Mappero reports - applications package missing: gstreamer0.10-plugins-good-extra
Extra decoders reports - applications package missing: gstreamer0.10-plugins-bad-extra
Are these apps broken forever?
Do you have the extras-testing repository enabled? See http://wiki.maemo.org/Extras-testing for details on what it means to enable extras-testing.
I haven't tried mappero, but extra decoders installs for me.
Just enable default repos(can't help with exact names as I use russian language),disable extras.It will help you.
Then in terminal download under root packages you need.