Don't take this the wrong way but it's you're fault. If ulx was according to your information
'that buggy', then it wouldn't be around for as long as it has been, nor would it be the leading administration system for garry's mod. There is an addon conflicting with ulx, could possibly be your dark rp server is conflicting with it, as you may have not gotten an official version of DarkRP, or have edited something you're not supposed to touch.
On the other hand, DarkRP works really well with ulx, as it has a modification called "FADMIN" (pretty sure it's called that), and it located in the TAB menu while playing DarkRP.
As I said somewhere above, you need to list all the addons you're using on your server. Easiest way is to check console at the beginning. I'll post below a code in red, and that's all the addons in your addons folder, and that's the easiest way for any of us to check what all your addons are, so just send us your list (same for if you're using working collaboration thing.)
My apologize ULX team, I know you guys hate long things, but I couldn't highlight in red with {code}Console initialized.
Adding Path: [C:\garrysmod_server\cstrike]
FIND [C:\garrysmod_server\cstrike\*.vpk]
ADDING [C:\garrysmod_server\cstrike\cstrike_pak_000.vpk]
Adding Path: [C:\garrysmod_server\tf]
FIND [C:\garrysmod_server\tf\*.vpk]
ADDING [C:\garrysmod_server\tf\tf2_misc_000.vpk]
ADDING [C:\garrysmod_server\tf\tf2_scripts_000.vpk]
Adding Path: [C:\garrysmod_server\dod]
FIND [C:\garrysmod_server\dod\*.vpk]
ADDING [C:\garrysmod_server\dod\dod_pak_000.vpk]
Adding Path: [C:\garrysmod_server\hl2mp]
FIND [C:\garrysmod_server\hl2mp\*.vpk]
ADDING [C:\garrysmod_server\hl2mp\hl2mp_pak_000.vpk]
Adding Path: [C:\garrysmod_server\portal]
FIND [C:\garrysmod_server\portal\*.vpk]
ConVarRef mat_dxlevel doesn't point to an existing ConVar
Game.dll loaded for "Garry's Mod"
Initializing Steam libraries for secure Internet server
Logging into anonymous gameserver account.
Connection to Steam servers successful.
Public IP is
Assigned anonymous gameserver Steam ID [A-1:1431694339(4942)].
VAC secure mode is activated.
Fetching Workshop Addons.. host_workshop_collection is unset
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\apple_chat_prefixes'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\apple_join_disconnect_warning'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\apple_multi_server_chat_sql'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\apply_last_join_server_sql'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\pointshopmaster'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulib'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulx'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulx_auto_promote'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulx_force_respawn'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulx_give_weapon'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulx_playurl'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulx_set_model'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulx_set_utime'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\ulx_temp_adduser'
Adding Filesystem Addon 'c:\garrysmod_server\garrysmod\addons\utime_sql'
Network: IP 192.168.0.7, mode MP, dedicated Yes, ports 27016 SV / 27006 CL
PREP OK