Comment 3 for bug 164709

The bug is a regression in the gutsy-backports repository with the 1.0~rc2-0ubuntu1 package. I don't think mplayer is to blame but probably the person that compiled the software and made the package didn't include the proper switches when configuring the software (./configure --with-some-option). I could be wrong, but this bug don't seem to be in the mplayer forums / lists I've searched so far. It looks ubuntu-specitific...

Workaround :
Downgrade to version 1.0~rc1-0ubuntu13.1 (repository gutsy-security) using synaptic / menu package / force version. You can also lock the new version so that update-notifier stop bothering you.