this seems to be a "missing dependency" problem. 
As my default kde install didn't come with banshee i had to post-install it,
but there seems to be packages missing (in banshees depencies).

Currently I am additionally installing the GNOME selections to see if it will 
work then with those packages in place.

yes, now with "GNOME System" also installed, banshee starts and plays without
problems!

Can you check which packages are missing?

Only the Gnome/Gnome-default selections contain any banshee packages. Which
banshee package did you install? Maybe there are missing requires to
banshee-engine-gst/banshee-engine-helix? I don't know.

This happens to me also with banshee-engine-helix

oh, installing banshee-engine-gst also fixed it for me. It seems some needed
stuff is only in that package?

I installed banshee on KDE only system and get the message:

lotmot@K21:~> banshee

Unhandled Exception: System.NullReferenceException: Object reference not set to
an instance of an object
in [0x00018] (at /usr/src/packages/BUILD/banshee-0.9.7/src/PlayerEngineLoader.cs
                           
         
:138) Banshee.PlayerEngineLoader:LoadEngines ()
in [0x00000] (at /usr/src/packages/BUILD/banshee-0.9.7/src/PlayerEngineLoader.cs
                           
         
:158) Banshee.PlayerEngineLoader:get_SelectedEngine ()
in [0x00067] (at /usr/src/packages/BUILD/banshee-0.9.7/src/Core.cs:145) Banshee.
                           
         
Core:.ctor ()
in [0x0000b] (at /usr/src/packages/BUILD/banshee-0.9.7/src/Core.cs:73) Banshee.C
                           
         
ore:get_Instance ()
in [0x000ef] (at /usr/src/packages/BUILD/banshee-0.9.7/src/Main.cs:78) Banshee.B
                           
         
ansheeEntry:Main (System.String[] args)


After installation of banshee-engine-gst and banshee-engine-helix, and I get
following:

lotmot@K21:~> banshee
Player Engine `GStreamer Engine' failed init tests... disabling (Could not
initialize GStreamer library)
0: Active Player Engine is now 'Helix'
1: Loaded PlayerEngine core: Helix
Could not load AudioCdPlayer!

Before the installation of the engines, its basically complaining that there are
no engines.  It should probably require one or the other.  Audio CD playing is
always done by gstreamer.

Looking at the code, the initialization failure of gstreamer is just not being
able to create a gstreamer object.  What gstreamer plugins are installed?

installed are gstreamer, gstreamer-plugins, and gstreamer-plugins-default

Please install the rest of the gstreamer plugins and see if that works.

btw: my first banshee install (that didn't startup) were the banshee and its
helix-engine package

I did it and it starts now. That means banshee installation on a KDE only system
lacks some dependant packages. Should be fixed as a YOU update IMO.

Yeah, and it plays mp3 files in KDE for the first time on my machine! Great! :)

So, it looks like we need to require all the gstreamer plugin packages (its
split) .  Technically i guess those requires should be on the engine packages
themselves.

For the audio CD I wish we could "recommend" a package.

We should also probably enforce atleast one engine when banshee install.s

Possible update candidate.

submitted to STABLE/PLUS.

AJ do you want to take this for as a 10.0 update?

I cannot take it for 10.0 since YOU will not handle this correctly :-(, it cannot
resolve dependencies during update.  this is something we have to fix...

reopening for release notes.

Let's write a release note for this.  Here's a draft:

Banshee Issues
==============

If you install banshee separatly (not together with the GNOME selection), then a
number of packages are missing.  You have to install these packages as well so
that banshee works correctly.  The packages are:

Note also that banshee will not play mp3 files under x86-64.

================

Gary,

Which packages need to get installed so that banshee works?

Ok, I'll take it but I need Gary's info.

Banshee Issues
==============

If you install banshee separatly (not together with the GNOME selection), then a
number of packages are missing.  You have to install these packages as well so
that banshee works correctly.  The packages are:

gstreamer-plugins-extra
gstreamer-plugins-excess

Note also that banshee will not play mp3 files under x86-64.

================

I only added the ones which are not already required by the package, did you
want me to add the others that are already listed?

Ok.  Karl, please add these.

It's in CVS now; I submit it later the day to the build system:

<sect3 id="banshee" status="2005-09-28">

   <title>Banshee Issues</title>
   <para>
If you install banshee separatly (not together with the GNOME selection), then a
number of packages are missing.  You have to install these packages as well so
that banshee works correctly.  The packages are:
</para>

   <itemizedlist>
    <listitem>
     <para><literal>gstreamer-plugins-extra</literal></para>
    </listitem>
    <listitem>
     <para><literal>gstreamer-plugins-excess</literal></para>
    </listitem>
   </itemizedlist>

   <para>Note also that banshee will not play MP3 files under x86-64.
</para>
  </sect3>

Please don't forget banshee-engine-gst, too.