I installed the steam versions of all three CoH games, and then installed Eastern Front. When click the play button on the launcher, it minimizes, then nothing happens. This is the warning I found in the Company of Heroes folder:
RELICCOH started at 2011-11-30 22:57
OS NT 6.1 (sp1.0) x64, 4095MB Physical Memory, 1744 Physical Available, 3969 Virtual Available
RUN-OPTIONS -dev -mod Eastern_Front -novsync -notriplebuffer
WORKING-DIR C:\Program Files (x86)\Steam\steamapps\common\company of heroes
USER Turner
22:57:31.76 4 Logical Processors detected
22:57:31.76 Multithreading Enabled
22:57:31.76 THREAD: Hyper-Threading Technology Processors are not detected.
22:57:31.76 XTHREAD: Detected 4 core(s) with 4 hardware thread(s)
22:57:31.76 XTHREAD: Main thread now used as XThread 0
22:57:31.77 XTHREAD: Spawned thread on processor 1
22:57:31.77 XTHREAD: Spawned thread on processor 2
22:57:31.77 XTHREAD: Spawned thread on processor 3
22:57:31.77 MATHBOX -- Version=6, Cpu=AMD Athlon 64:f=16,m=5, Mode=SSE
22:57:31.77 GAME -- Company Of Heroes, 2.602.0, Build live.2.602.0, Type live, Language English
22:57:31.77 MOD -- Couldn't find mod 'Eastern_Front'!
22:57:31.77 GAME -- Failed to initialize mod Eastern_Front.
22:57:31.77 FE -- Failed to init MOD!
22:57:31.77 LoadDevicesInit -- Failed load for step: 'ModManager'
22:57:31.77 APP -- The application failed to initialize it's devices, code: 2
Application closed without errors