After some tweaking and fiddling, we have hit upon some fixes for some of the crashes that may occur playing on some of the Darkest Hour servers, the Jolly Rodger tank server in particular.

First, get the program Large Address Aware here.
You can put the executable from the .zip anywhere, best to put it near where your games are. Run the LAA.exe file, then locate your Red Orchestra .exe file, if it is from Steam the .exe will be under "*/Steam/Steamapps/common/red orchestra/system". Click the checkbox to patch it to use more than 2Gigs of RAM.

Next, go to the "*/Steam/Steamapps/common/red orchestra/DarkestHour/system" folder. In here you should see a DarkestHour.ini file. Open this with Notepad and make the following changes:

1) Change the cache size to better match your ram size
Listed under [Engine.GameEngine].
CacheSizeMegs=512
If you have less than 4 Gig of memory,
CacheSizeMegs=256

2) Turn off PreCaching
Also in your DarkestHour.ini under [ALAudio.ALAudioSubsystem]
Change UsePrecache=True to UsePrecache=False
and under [Engine.LevelInfo]
Change bNeverPrecache=false to bNeverPrecache=true
and under [Engine.NullRenderDevice]
Change UsePrecaching=True to UsePrecaching=False
and under [D3DDrv.D3DRenderDevice]
Change UsePrecaching=True to UsePrecaching=False
and under [D3D9Drv.D3D9RenderDevice]
Change UsePrecaching=True to UsePrecaching=False
and under [OpenGLDrv.OpenGLRenderDevice]
Change UsePrecaching=True to UsePrecaching=False
and under [PixoDrv.PixoRenderDevice]
Change UsePrecaching=True to UsePrecaching=False

3) Increase the resolution size. You have to do it here as the ingame won't let you go to very high resolutions.
Under [WinDrv.WindowsClient]
Change all the below to match your native Windows resolution. Mine is 1920x1080.
WindowedViewportX=1920
WindowedViewportY=1080
FullscreenViewportX=1920
FullscreenViewportY=1080

4) Save the file.

Okay, you should be ready to rock and roll. Start Darkest Hour and enjoy!