LinuxQuestions.org - Mplayer error /dev/mixer

I am running Mandrake 10.1

I installed Mplayer with urpmi.

When I try to open a video file from the GUI I get the error

alsa control mixer attach /dev/mixer error: No such file or directory

If I run it by terminal, the video plays correctly, the audio for some file works and for others not.

The message I get in the terminal is

MPlayer 1.0pre5-3.4.1 (C) 2000-2004 MPlayer Team

CPU: Intel Pentium III Katmai/Pentium III Xeon Tanner 548.0 MHz (Family: 6, Stepping: 3)
Detected cache-line size is 32 bytes
CPUflags: MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 0
Compiled with runtime CPU detection - WARNING - this is not optimal!
To get best performance, recompile MPlayer with --disable-runtime-cpudetection.
Reading config file /etc/mplayer/mplayer.conf
Reading config file /home/zeus/.mplayer/config
Reading /home/zeus/.mplayer/codecs.conf: Can't open '/home/zeus/.mplayer/codecs.conf': No such file or directory
Reading /etc/mplayer/codecs.conf: 73 audio & 180 video codecs
Failed to open /dev/rtc: No such file or directory (it should be readable by the user.)
Using usleep() timing
Can't open input config file /home/zeus/.mplayer/input.conf: No such file or directory
Input config file /etc/mplayer/input.conf parsed: 53 binds
Opening joystick device /dev/input/js0
Can't open joystick device /dev/input/js0 : No such file or directory
Can't init input joystick
Setting up LIRC support...
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support.
You will not be able to use your remote control.

Playing happy_birthday.wmv.
Cache fill: 9,83% (824856 bytes) ASF file format detected.
VIDEO: [WMV3] 320x240 24bpp
Clip info:
name:
author:
copyright:
comments:
==========================================================================
Trying to force audio codec driver family libmad...
Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
AUDIO: 44100 Hz, 2 ch, 16 bit (0x10), ratio: 8005->176400 (64,0 kbit)
Selected audio codec: [ffwmav2] afm:ffmpeg (DivX audio v2 (ffmpeg))
==========================================================================
vo: X11 running at 1024x768 with depth 24 and 32 bpp (":0.0" => local display)
==========================================================================
Opening video decoder: [dmo] DMO video codecs
External func OLEAUT32.dll:8
DMO dll supports VO Optimizations 0 1
DMO dll might use previous sample when requested
GetOutput r=0x0 size:230400 align:1
StreamCount r=0x0 1 1
Decoder supports the following YUV formats: YV12 YUY2 UYVY YVYU ▒
Decoder is capable of YUV output (flags 0x1b)
VDec: vo config request - 320 x 240 (preferred csp: Packed YUY2)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is undefined - no prescaling applied.
VO: [xv] 320x240 => 320x240 Planar YV12 [zoom]
Selected video codec: [wmv9dmo] vfm:dmo (Windows Media Video 9 DMO)
==========================================================================
Checking audio filter chain for 44100Hz/2ch/16bit -> 44100Hz/2ch/16bit...
AF_pre: af format: 2 bps, 2 ch, 44100 hz, little endian signed int
AF_pre: 44100Hz 2ch Signed 16-bit (Little-Endian)
audio_setup: Can't open audio device /dev/dsp: No such file or directory
alsa-init: got device=0, subdevice=0
alsa-init: 1 soundcard found, using: default
alsa: 44100 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit Little Endian
AO: [alsa] 44100Hz 2ch Signed 16-bit (Little-Endian) (2 bps)
Building audio filter chain for 44100Hz/2ch/16bit -> 44100Hz/2ch/16bit...
Starting playback...
alsa-space: xrun of at least 26,972 msecs. resetting stream 0,8% 6 0 0%
A: 16,2 V: 16,2 A-V: -0,027 ct: -0,055 307/307 16% 7% 0,8% 6 0 0%
alsa-uninit: pcm closed

Any hint how to fix?