This bug seems to be common so I'll chip in my log file to help debug it.

System specs:
P4 2ghz 512 mb
Red Hat 7.2 
KDE desktop
Kernel 2.4.7-10
GeForce 4 Ti 4200 (Nvidia 53.36 drivers)


Log: Log file open, Sun Mar 21 22:29:08 2004
Init: Name subsystem initialized
Log: Your locale: [ISO-8859-1].

Init: Version: 3186 (127.29)
Init: Compiled: Mar  4 2004 03:07:41
Init: Command line: 
Init: (This is Linux patch version 3186.0)
Init: Character set: Unicode
Init: Base directory: /usr/local/games/ut2004/System/
Init: Ini:UT2004.ini   UserIni:User.ini
Init: Build label: UT2004 Build UT2004_Build_[2004-03-03_02.42]
Init: Object subsystem initialized
Warning: Missing Class Class Editor.TransBuffer
Log: Initializing OpenGLDrv...
Log: binding libGL.so.1
Log: Global MD5: [3986c4774f86cab155ff9f5432b89282]
Log: Game class is 'GameInfo'
Log: Bringing Level Entry.myLevel up for play (0) appSeconds: 5.361355...
ScriptLog: GameInfo::InitGame : bEnableStatLogging False
Log: Browse:
NvidiaLogo.ut2?Name=Lucid_Dream?Class=Engine.Pawn?Character=Corrosion?team=255?Sex=M?SpectatorOnly=1
Log: Collecting garbage
Log: Purging garbage
Log: Garbage: objects: 32782->32781; refs: 339619
Log: Game class is 'CinematicGame'
Log: Bringing Level NvidiaLogo.myLevel up for play (0) appSeconds: 6.564196...
ScriptLog: GameInfo::InitGame : bEnableStatLogging False
Log: Created and initialized a new SDL viewport.
Log: ALAudio: Using ALC_EXT_capture to record audio.
Log: SET PLAYER!
ScriptLog: New Player Lucid_Dream id=50af31edfe5debf6626ae3239d263657
Log: TTS: No output filename specified.
Log: Enter SetRes: 1024x768 Fullscreen 1
Log: OpenGL
Log: GL_VENDOR     : NVIDIA Corporation
Log: GL_RENDERER   : GeForce4 Ti 4200 with AGP8X/AGP/SSE2
Log: GL_VERSION    : 1.4.1 NVIDIA 53.36
Log: OpenGL: Device supports: GL
Log: OpenGL: Device supports: GL_EXT_bgra
Log: OpenGL: Device supports: GL_ARB_texture_compression
Log: OpenGL: Device supports: GL_EXT_texture_compression_s3tc
Log: OpenGL: Device supports: GL_ARB_texture_cube_map
Log: OpenGL: Device supports: GL_ARB_texture_env_combine
Log: OpenGL: Device supports: GL_NV_texture_env_combine4
Log: OpenGL: Device supports: GL_EXT_texture_lod_bias
Log: OpenGL: Device supports: GL_ARB_multitexture
Log: OpenGL: Device supports: GL_NV_vertex_array_range
Log: OpenGL: Device supports: GL_NV_vertex_array_range2
Log: OpenGL: Device supports: GL_ARB_multisample
Log: OpenGL: Device supports: GL_NV_multisample_filter_hint
Log: OpenGL: Device supports: GL_EXT_texture_filter_anisotropic
Log: OpenGL: Device supports: GL_ARB_vertex_buffer_object
Log: OpenGL: C32 RGB888 Z24 S8
Log: OpenGL: Level of anisotropy is 1.000000 (max 8.000000).
Log: OpenGL: Have 0 multisamples buffers, 0 samples.
Log: OpenGL: Failed to get a multisample GL context
Log: OpenGL: allocated 32 MByte of AGP memory
Log: Startup time: 7.061203 seconds
Log: Precaching: NvidiaLogo.LevelInfo0
Log: Static mesh batches: 508608 vertex bytes, 110460 index bytes
Log: Allocating 32768 byte dynamic index buffer.
Log: Allocating 65536 byte dynamic vertex buffer.
Log: Finished precaching geometry in 0.052 seconds
Log: Finished precaching textures in 0.104 seconds
Debug: UT2k4MainMenu.Opened()   Sender:Package.UT2k4MainMenu
Log: URL: Adding default option Name=Lucid_Dream
Log: URL: Adding default option Class=Engine.Pawn
Log: URL: Adding default option Character=Corrosion
Log: URL: Adding default option team=255
Log: Browse:
Index.ut2?disconnect?Name=Lucid_Dream?Class=Engine.Pawn?Character=Corrosion?team=255
Log: Failed; returning to Entry
ScriptLog: UT2k4MainMenu NotifyLevelChange  PendingConnection:False
Log: GP=FALSE
Log: Spawning new actor for Viewport SDLViewport
Log: SET PLAYER!
ScriptLog: New Player Lucid_Dream id=50af31edfe5debf6626ae3239d263657
Log: Static mesh batches: 0 vertex bytes, 0 index bytes
Warning: Missing TexEnvMap TexEnvMap CubeMaps.Skins.Skin0_EnvMapCoords
Debug: UT2k4MainMenu.Opened()   Sender:None
ScriptLog: Attempting to close a non-existing menu page
Log: URL: Adding default option Name=Lucid_Dream
Log: URL: Adding default option Class=Engine.Pawn
Log: URL: Adding default option Character=Corrosion
Log: URL: Adding default option team=255
Log: Browse:
ONS-Primeval?LinkSetup=Default?Game=Onslaught.ONSOnslaughtGame?bAutoNumBots=True?Name=Lucid_Dream?Class=Engine.Pawn?Character=Corrosion?team=255
Log: Collecting garbage
Log: Purging garbage
Log: (Karma): Level Karma Terminated.
Log: Garbage: objects: 40113->37540; refs: 474496
Log: Game class is 'ONSOnslaughtGame'
Log: Bringing Level ONS-Primeval.myLevel up for play (0) appSeconds: 26.450882...
ScriptLog: GameInfo::InitGame : bEnableStatLogging False
ScriptLog: bAutoNumBots: True
ScriptLog: Using Official Link Setup: Default
Log: Spawning new actor for Viewport SDLViewport
Log: SET PLAYER!
ScriptLog: New Player Lucid_Dream id=50af31edfe5debf6626ae3239d263657
Log: Precaching: ONS-Primeval.LevelInfo0
Log: Static mesh batches: 3264912 vertex bytes, 420906 index bytes
Log: Allocating 32768 byte dynamic index buffer.
Log: Allocating 273072 byte dynamic index buffer.
Log: Allocating 65536 byte dynamic vertex buffer.
Log: Allocating 331776 byte dynamic vertex buffer.
Log: Finished precaching geometry in 0.704 seconds
Log: Finished precaching textures in 4.815 seconds
ScriptLog: START MATCH
Log: (Karma:) Excessive Joint Error. Destroying RagDoll.
Log: (Karma:) Excessive Joint Error. Destroying RagDoll.
Log: (Karma:) Ragdoll Bounding Box invalid or outside world.
Log: Preprocessing:  Vertex stream total vertices: 62 Orig wedges: 62
Log: (Karma:) Ragdoll Bounding Box invalid or outside world.
Log: Octree Warning (AddActor): xPawn Outside World.
Log: (Karma:) Excessive Joint Error. Destroying RagDoll.
ScriptLog: Reset Onslaught.
Log: Collecting garbage
Log: Purging garbage
Log: Garbage: objects: 41530->40846; refs: 529249
Log: 
Developer Backtrace:
Log: [ 1]  ./ut2004-bin [0x86c915c]
Log: [ 2]  /lib/i686/libpthread.so.0 [0x400348d5]
Log: [ 3]  /lib/i686/libc.so.6 [0x400fc848]
Log: [ 4]  ./ut2004-bin [0x81d30b0]
Log: [ 5] 
./ut2004-bin(KHandleCollisions__FP22_McdModelPairContainerP6ULevel+0xdd) [0x81d31f9]
Log: [ 6]  ./ut2004-bin(KUpdateContacts__FRt6TArray1ZP6AActorP6ULeveli+0x74f)
[0x81d11c3]
Log: [ 7]  ./ut2004-bin(KTickLevelKarma__FP6ULevelf+0x234) [0x8603028]
Log: [ 8]  ./ut2004-bin(Tick__6ULevel10ELevelTickf+0x35b) [0x82df03b]
Log: [ 9]  ./ut2004-bin(Tick__11UGameEnginef+0x3cf) [0x82889b7]
Log: [10]  ./ut2004-bin(SDL_SetVideoMode+0x83f) [0x814dac3]
Log: [11]  ./ut2004-bin(main+0x69bc) [0x815849c]
Log: [12]  /lib/i686/libc.so.6(__libc_start_main+0x93) [0x400ea507]
Log: [13]  ./ut2004-bin(getlogin+0xad) [0x814d361]
Log: Unreal Call Stack: KIntersect <- KIntersectEach <- KHandleCollisions <-
KUpdateContacts <- KTickLevelKarma <- TickAllActors <- ULevel::Tick <- TickLevel
<- UGameEngine::Tick <- UpdateWorld <- MainLoop
Exit: Exiting.
Log: FileManager: Reading 0 GByte 239 MByte 649 KByte 656 Bytes from HD took
12.209258 seconds (7.625397 reading, 4.583861 seeking).
Log: FileManager: 0.000000 seconds spent with misc. duties
Uninitialized: Name subsystem shut down
Uninitialized: Allocation checking disabled
Uninitialized: Log file closed, Sun Mar 21 23:02:28 2004