[Crash] Help please I need it!

[HELP]

OK i load a map online and its all hunky dory and fun then the round ends new map, then it crash and says something liek this Build RedOrchestra_Build_[2005-11-27_10.48]

OS: Windows NT 6.0 (Build: 6000)
CPU: GenuineIntel PentiumPro-class processor @ 1496 MHz with 2047MB RAM
Video: NVIDIA GeForce 8400M GS (9562)

IDirect3DVertexBuffer9::Lock failed(80004005).

History: FD3D9VertexStream::Cache <- FD3D9RenderInterface::SetVertexStreams <- ATerrainInfo::Render <- RenderLevel <- DH-River_Crossing_Winter_V6.myLevel <- FLevelSceneNode::Render <- RenderLevel <- DH-River_Crossing_Winter_V6.myLevel <- FLevelSceneNode::Render <- RenderLevel <- DH-River_Crossing_Winter_V6.myLevel <- FLevelSceneNode::Render <- RenderLevel <- DH-River_Crossing_Winter_V6.myLevel <- FLevelSceneNode::Render <- FPlayerSceneNode::Render <- UGameEngine:raw <- UWindowsViewport::Repaint <- UWindowsClient::Tick <- ClientTick <- UGameEngine::Tick <- Level River Crossing Winter <- UpdateWorld <- MainLoop <- FMallocWindows::Free <- FMallocWindows::Realloc <- 4C576C61 0 FArray <- FArray::Realloc <- 0*2 <- FMallocWindows::Free plz help! thx