I'm getting this problem with FreeBSD:
  -bash-2.05b$ uname -a
 FreeBSD srv.escapedturkey.com 4.9-PRERELEASE FreeBSD 4.9-PRERELEASE #0: Sat Sep 20 04:53:17 GMT 2003 [Redacted]@[Redacted].[Redacted]:/usr/obj/usr/src/sys/whatever i386
 -bash-2.05b$ 
 Startup: 
 screen ./linuxjampded +set dedicated 2 +set net_ip 69.50.183.227 +set net_port 29070 +set ttycon 0 +set fs_homepath /usr/home/turkey +set com_hunkmegs 64 +set sv_maxclients 16 +exec server.cfg 
 Using the default server.cfg to test: 
 // Server Config
 seta sv_hostname "my server name"
 //seta g_motd "woot" 
 //rconpassword "my secret password" 
 seta sv_maxclients 16 
 set timelimit 20
 // gametypes
 // 0 = FFA
 // 3 = DUEL one on one tournament
 // 4 = POWER DUEL
 // 6 = TEAM DEATHMATCH
 // 7 = SIEGE
 // 8 = CTF 
 // below will rotate through all multiplayer maps
 // found in the assets0.pk3 file and use the correct
 // gametype for each map
 set d1 "set g_gametype 0; map mp/ffa1 ; set nextmap vstr d2"
 set d2 "set g_gametype 0; map mp/ffa2 ; set nextmap vstr d3"
 set d3 "set g_gametype 0; map mp/ffa3 ; set nextmap vstr d4"
 set d4 "set g_gametype 0; map mp/ffa4 ; set nextmap vstr d5"
 set d5 "set g_gametype 0; map mp/ffa5 ; set nextmap vstr d6"
 set d6 "set g_gametype 8; map mp/ctf1 ; set nextmap vstr d7"
 set d7 "set g_gametype 8; map mp/ctf5 ; set nextmap vstr d8"
 set d8 "set g_gametype 8; map mp/ctf5 ; set nextmap vstr d9"
 set d9 "set g_gametype 8; map mp/ctf5 ; set nextmap vstr d10"
 set d10 "set g_gametype 8; map mp/ctf5 ; set nextmap vstr d11"
 set d11 "set g_gametype 3; map mp/duel1 ; set nextmap vstr d12"
 set d12 "set g_gametype 3; map mp/duel2 ; set nextmap vstr d13"
 set d13 "set g_gametype 3; map mp/duel3 ; set nextmap vstr d14"
 set d14 "set g_gametype 3; map mp/duel4 ; set nextmap vstr d15"
 set d15 "set g_gametype 3; map mp/duel5 ; set nextmap vstr d16"
 set d16 "set g_gametype 3; map mp/duel6 ; set nextmap vstr d17"
 set d17 "set g_gametype 3; map mp/duel7 ; set nextmap vstr d18"
 set d18 "set g_gametype 3; map mp/duel8 ; set nextmap vstr d19"
 set d19 "set g_gametype 3; map mp/duel9 ; set nextmap vstr d20"
 set d20 "set g_gametype 3; map mp/duel10 ; set nextmap vstr d21"
 set d21 "set g_gametype 7; map mp/siege_desert ; set nextmap vstr d22"
 set d22 "set g_gametype 7; map mp/siege_hoth ; set nextmap vstr d23"
 set d23 "set g_gametype 7; map mp/siege_korriban ; set nextmap vstr d1" 
 // start the first map
 vstr d1 
 It goes to this and I have to hit CTRL C to stop it:  
 JAmp: v1.0.1.0 linux-i386 Sep 19 2003
 ----- FS_Startup -----
 Current search path:
 /usr/home/escaped/base
 /usr/home/escaped/ja/base/assets2.pk3 (62 files)
 /usr/home/escaped/ja/base/assets1.pk3 (8320 files)
 /usr/home/escaped/ja/base/assets0.pk3 (15346 files)
 /usr/home/escaped/ja/base
 ./linuxjampded/base 
 ----------------------
 23728 files in pk3 files
 execing mpdefault.cfg
 couldn't exec jampserver.cfg
 couldn't exec autoexec.cfg
 --- Common Initialization Complete ---
 Opening IP socket: 69.50.183.227:29070
 Hostname: srv.escapedturkey.com
 IP: 216.234.168.7
 execing server.cfg
 ------ Server Initialization ------
 Server: mp/ffa1
 ----- FS_Startup -----
 Current search path:
 /usr/home/escaped/base
 /usr/home/escaped/ja/base/assets2.pk3 (62 files)
 /usr/home/escaped/ja/base/assets1.pk3 (8320 files)
 /usr/home/escaped/ja/base/assets0.pk3 (15346 files)
 /usr/home/escaped/ja/base
 ./linuxjampded/base 
 ----------------------
 47456 files in pk3 files
 Loading dll file jampgame.
 Sys_LoadDll(/usr/home/escaped/ja/base/jampgamei386.so)...
 Sys_LoadDll(jampgame) found **vmMain** at 0x2a0cbbb8
 Sys_LoadDll(jampgame) succeeded!
 ------- Game Initialization -------
 gamename: basejk
 gamedate: Sep 9 2003  
 That's it, just hangs there. I have JK2 running on the same machine and it's running just fine. I followed the instructions for the FreeBSD install here:  
http://forums.ravensoft.com/ib/ikonboard.pl?act=ST;f=21;t=24916) 
 Hrm. :(