hello,
I recompiled Mplayer on 64 bit by installing 32bit codec from Mplayer site to /usr/local/codecs but still mplayer is not playing .asf files. so what can i do?

You need the 32bit version of mplayer. The win32 codecs wont work with 64 bit players.

so what i have to do? i downloaded mplayer source and compiled. how can i build 32 bit mplayer on my 64 bit machine?

what works for me.

export CC="gcc -m32"
export LDFLAGS='-L/usr/X11R6/lib'
./configure
make
make install

BUT, Initially you will need a whole bunch of -devel libraries before you get it to work.

Better alternative

yum install yumex

setup yum repository from here
http://freshrpms.net/packages/

with yumex you can force i386 id, so that it will look in the correct directory (the 32 bit one).

hello,
I am using RHEL4 64 bit. so no yum usage for me.
i did as you said and got following error
gcc -m32 -c -I../libvo -I../../libvo -I/usr/X11R6/include -O4 -pipe -ffast-math -fomit-frame-pointer -D_REENTRANT -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I. -I/usr/include/cdda -I/usr/X11R6/include -o mplayer.o mplayer.c
In file included from libmpdemux/dvbin.h:11,
from mplayer.c:113:
libmpdemux/dvb_defaults.h:73:3: warning: #warning No DVB-T country defined in dvb_defaults.h, defaulting to UK. Ignore this if using Satellite or Cable.
gcc -m32 -c -I../libvo -I../../libvo -I/usr/X11R6/include -O4 -pipe -ffast-math -fomit-frame-pointer -D_REENTRANT -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I. -I/usr/include/cdda -I/usr/X11R6/include -o mp_msg.o mp_msg.c
gcc -m32 -c -I../libvo -I../../libvo -I/usr/X11R6/include -O4 -pipe -ffast-math -fomit-frame-pointer -D_REENTRANT -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I. -I/usr/include/cdda -I/usr/X11R6/include -o cpudetect.o cpudetect.c
{standard input}: Assembler messages:
{standard input}:2511: Error: bad register name `%rbx'
{standard input}:2513: Error: bad register name `%rbx'
{standard input}:2535: Error: bad register name `%rbx'
{standard input}:2537: Error: bad register name `%rbx'
{standard input}:2586: Error: bad register name `%rbx'
{standard input}:2588: Error: bad register name `%rbx'
{standard input}:2654: Error: bad register name `%rbx'
{standard input}:2656: Error: bad register name `%rbx'
{standard input}:2679: Error: bad register name `%rbx'
{standard input}:2681: Error: bad register name `%rbx'
make: *** [cpudetect.o] Error 1

not sure perhaps -L/usr/X11R6/lib is different on your distro. In any case I found this
http://ftp.wl0.org/RPMS-rhel4-various/