Comment 3 for bug 390011

problem solved for me:
after searching on google I've found this: http://bugs.gentoo.org/219278
and indeed, the solution found there works:

$ LANG=en_US.utf8 gupnp-universal-cp
** (gupnp-universal-cp:11652): WARNING **: Failed to load icon gtk-missing-image: Icon 'image-missing' not present in theme
** (gupnp-universal-cp:11652): WARNING **: Failed to load icon gtk-network: Icon 'network-workgroup' not present in theme
** (gupnp-universal-cp:11652): WARNING **: Failed to load icon (null): Icon 'audio-x-generic' not present in theme
**
ERROR:icons.c:317:init_icons: assertion failed: (icons[i] != NULL)

$ cat ~/.gtkrc-2.0-kde4
include "/usr/share/themes/QtCurve/gtk-2.0/gtkrc"
$ mv ~/.gtkrc-2.0-kde4 ~/.gtkrc-2.0-kde4_
$ echo -e "gtk-icon-theme-name=\"gnome\"" >>~/.gtkrc-2.0
$ LANG=en_US.utf8 gupnp-universal-cp # <- program runs!

so it's a problem with the themes...