this is the first time i tried to play doom 3 on my new amd64 system and i get

DOOM 1.1.1286 linux-x86 Nov 24 2004 17:56:04
Hostname: Gentoo
local IP: 192.168.0.102
------ Initializing File System ------
Loaded pk4 /opt/doom3/base/game00.pk4 with checksum 0x7dafc4d4
Loaded pk4 /opt/doom3/base/game01.pk4 with checksum 0x16cf3b8a
Loaded pk4 /opt/doom3/base/pak000.pk4 with checksum 0x28d208f1
Loaded pk4 /opt/doom3/base/pak001.pk4 with checksum 0x40244be0
Loaded pk4 /opt/doom3/base/pak002.pk4 with checksum 0xc51ecdcd
Loaded pk4 /opt/doom3/base/pak003.pk4 with checksum 0xcd79d028
Loaded pk4 /opt/doom3/base/pak004.pk4 with checksum 0x765e4f8b
Loaded pk4 /opt/doom3/base/pak005.pk4 with checksum 0x8ffc3621
Current search path:
/home/frenchy/.doom3/base
/opt/doom3/base
/opt/doom3/base/pak005.pk4 (63 files)
/opt/doom3/base/pak004.pk4 (5137 files)
/opt/doom3/base/pak003.pk4 (4676 files)
/opt/doom3/base/pak002.pk4 (6120 files)
/opt/doom3/base/pak001.pk4 (8972 files)
/opt/doom3/base/pak000.pk4 (2698 files)
/opt/doom3/base/game01.pk4 (2 files)
/opt/doom3/base/game00.pk4 (2 files)
game DLL: 0x0 in pak: 0x0
file system initialized.
--------------------------------------
----- Initializing Decls -----
------------------------------
------- Initializing renderSystem --------
using ARB renderSystem
renderSystem initialized.
--------------------------------------
5151 strings read from strings/english.lang
Couldn't open journal files
execing editor.cfg
execing default.cfg
couldn't exec DoomConfig.cfg
couldn't exec autoexec.cfg
5151 strings read from strings/english.lang
----- Initializing Sound System ------
sound system initialized.
--------------------------------------
----- R_InitOpenGL -----
Setup X display connection
dlopen(libGL.so.1)
dlopen(libGL.so.1)
idRenderSystem::Shutdown()
Xlib: extension "XFree86-DGA" missing on display ":0.0".
signal caught: Segmentation fault
si_code 1
Was in fatal error shutdown: Unable to initialize OpenGL
Trying to exit gracefully..


ive commented the stuff about omit xfree86-dga in xorg.conf but it still doesnt work.

Doom3 is 32 bit. You need to install the 32bit compatible system libraries so you can run 32 bit apps.

Read up buttercup:

http://zerowing.idsoftware.com/linux/doom/

tat lik you gave me said it will run on a 64 bit environment it didnt say anything about 32 bit libs.

There's a few posts like this on the Gentoo forums - what graphics card & driver are you using?

Have a read here and here (the solution in the 2nd thread looks nice and simple, I haven't actually tried it)