Audio/Sound problem

[sister_the]

Main problem: No sound in headphones :!:

Here is some information about my system:

Windows XP Pro servicepack 2
Intel P4(R), CPU 3.00 GHz
1.00 GB of RAM

AC3 filter, Version 1.11
ffdshow, cannot find version number
Bsplayer Pro Version 2.12
Sound: C-Media 3D Audio
Audica CODEC CMI 9880L
Audio driver version 5.12.0007.32
Direct X 9.0b
C-Media Audio configuration Version 1.0.42.10
And im using SPDIF output to my reciver

Problem information
When iam playing a movie - lets say an AVI movie - with AC3 5.1 sound, it work perfect with my reciver. It can handle SPDIF.
BUT if i want to hear the sound in my headphones it doesn't work. They are dead.

Theres no problem with the headphones. Winamp and other stuff works. Also VLC.

I want to have sound in my headphones and in my reciver.
Waht could the problem be? how to set my preferences right?