I've just downloaded the new DLC on Steam, and everythin looked fine, until i recognized that i can't play on new maps, @ listed servers their name isn't shown, & i cant join.
But new abilities, outfits e.g. do work..
What shall i do :@

I got this problem too, I tried playing through airport on security and at the end of the mission I selected next mission but I ended up at aquarium. The maps didn't work for us and I really don't want to reinstall the game.

If Steam would at least let us deinstall the DLC -.-'
I hate the fact that I've waited the whole day for THAT

Not necessarily, the content was probably delivered via patch not by buying / downloading DLC. Otherwise how would you see the new content on other players?

I too also am having this issue

Same for me here, Have deleted game content and re-downloading just in case ...

So my DLC isn't working at all. I keep getting this error

------ Initializing File System ------
Loaded pak000.sdpk2
Loaded pak001.sdpk2
Loaded pak002.sdpk2
Loaded pak003.sdpk2
Loaded pak004.sdpk2
Loaded pak005.sdpk2
Loaded pak006.sdpk2
Loaded pak007.sdpk2
Loaded zzzdlcenglish000.sdpk2
Loaded zzzenglish000.sdpk2
Loaded zzzenglish001.sdpk2
Loaded zzzenglish002.sdpk2
Loaded zzzenglish003.sdpk2
Loaded zzzenglish004.sdpk2
Loaded zzzenglish005.sdpk2
Loaded zzzenglish006.sdpk2
Current search path:
C:\Program Files (x86)\Steam\userdata\80969549\22350\local/base
C:\Users\Krysis Realm\AppData\Local\Splash Damage\Brink/base
c:\program files (x86)\steam\steamapps\common\brink/base
zzzenglish006.sdpk2
zzzenglish005.sdpk2
zzzenglish004.sdpk2
zzzenglish003.sdpk2
zzzenglish002.sdpk2
zzzenglish001.sdpk2
zzzenglish000.sdpk2
zzzdlcenglish000.sdpk2
pak007.sdpk2
pak006.sdpk2
pak005.sdpk2
pak004.sdpk2
pak003.sdpk2
pak002.sdpk2
pak001.sdpk2
pak000.sdpk2
file system initialized.
--------------------------------------
Loaded 3783 manifest elements in 9 ms - 192Kb
Discarded 0 manifest elements
Max filename length: 0 characters
Brink 1.0.23653.48097 win-x86 Jul 29 2011 11:29:57
execing 'brinkconfig.cfg'
r_multiSamples is read only.
couldn't exec 'autoexec.cfg'
Vendor: 10DE Device: 0618
2527 MHz Intel CPU with MMX & SSE & SSE2 & SSE3 & HTT
2 logical cores
2 physical cores
HT disabled in hardware
6144 MB System Memory
1024 MB Video Memory
Initializing performance queries
Winsock Initialized
Found interface: {F0128657-7ACD-4453-A34C-B4011A1D29A3} Realtek RTL8168C(P)/8111C(P) Family PCI-E Gigabit Ethernet NIC (NDIS 6.20) - 0.0.0.0 NULL ip - skipped
Found interface: {6A616E41-AF93-42FE-AD1C-A6B48ADBD3C1} Atheros AR928X Wireless Network Adapter - 192.168.1.14/255.255.255.0
Sys_InitNetworking: adding loopback interface
--- Loading sequence: init ---
sound index file 'generated/preload/sound/pc/english/init.soundpreload' is zero length
------- Initializing render context --------
Initializing OpenGL subsystem
...calling LoadLibrary( 'wtsapi32.dll' ): succeeded
...initializing Windows Terminal Server API
...registered window class
...registered fake window class
...calling LoadLibrary( 'opengl32' ): succeeded
...initializing QGL
GL_VENDOR: NVIDIA Corporation
GL_RENDERER: GeForce GTX 260M/PCI/SSE2
GL_VERSION: 3.0.0
********************
FATAL ERROR: The current video card / driver combination does not support OpenGL 3.1 or newer.
********************
The current video card / driver combination does not support OpenGL 3.1 or newer.
Shutting down OpenGL subsystem
...releasing DC
...resetting display
...shutting down QGL
...unloading OpenGL DLL
...unloading Windows Terminal Server API DLL

Any Ideas as to WTF is going on?

Ok I did the unthinkable and reinstalled my game. Luckily since this is Steam were talking about, all my stuff is saved so its only a minor inconvenience. Now the maps work.

Ok, I'll try to reinstall it too now.