Command Line Rendering fails

[yaoyansi]

test case:
set LIQUID_ROOT=E:\liquid_
render -r "liquid" %LIQUID_ROOT%\2.3.3\test\test_er_shader\er_shader_lambert.ma

No image is output, and here is log:
Starting "D:\Program Files\Autodesk\Maya2009\bin\mayabatch.exe"
mental ray for Maya 10.0
mental ray: version 3.7.1.26, Jul 30 2008, revision 26576
This is elvishray /2.3.3/src/elvishray/mel/usersetup.mel.
Initializing Liquid v2.3.5 (buildtime=23:43:31.23)
Initial Liquid code by Colin Doncaster
Liquid 2.3.5 (buildtime=23:43:31.23) registered
File read in 1 seconds.
Result: E:/liquid_/2.3.3/test/test_er_shader/er_shader_lambert.ma
Warning: global string $renderer[] = {"renderman", "elvishray", "luxrenderer"};
Warning: Global variable is already initialized; this occurrence is ignored.
liquidRenderer.xml
>registerLiquidRenderer()
>liquidAddTabs()
>liquidmayaCmdlineRender(...)
[Liquid] Using project base path 'E:/MyDocuments/maya/projects/default/'
[Liquid] _doItNew()
[Liquid] useRenderScript=0
[Liquid] Creating RIB ...
[Liquid] Starting to loop through frames
[Liquid] , 000 000 000 00

[Liquid] |groundPlane_transform, 000 000 000 00

[Liquid] |groundPlane_transform|groundPlane, 000 000 000 00

[Liquid] |persp, 000 000 000 00

[Liquid] |persp|perspShape, 000 000 000 00

[Liquid] |top, 000 000 000 00

[Liquid] |top|topShape, 000 000 000 00

[Liquid] |front, 000 000 000 00

[Liquid] |front|frontShape, 000 000 000 00

[Liquid] |side, 000 000 000 00

[Liquid] |side|sideShape, 000 000 000 00

[Liquid] |pCube1, 000 000 000 00

[Liquid] |pCube1|pCubeShape1, 010 000 000 00

[Liquid] |pointLight1, 000 000 000 00

[Liquid] |pointLight1|pointLightShape1, 000 000 000 00

[Liquid] |camera1, 000 000 000 00

[Liquid] |camera1|cameraShape1, 000 000 000 00

[Liquid] |pointLight2, 000 000 000 00

[Liquid] |pointLight2|pointLightShape2, 000 000 000 00

[Liquid] Beginning RIB output to 'E:/MyDocuments/maya/projects/default/rib/cameraShape1.0001.rib'
INFO> Starting up network...
INFO> nthreads 0
INFO> memlimit 512
INFO> distributed off
INFO> server 127.0.0.1:6666
INFO> searchpath E:/liquid/dependence/elvishray/trunk/build/r1008/x86_D
ebug
INFO> Memory limit set to 512 MB
INFO> Local rendering threads: 2
INFO> Remote rendering threads: 0
[Liquid] output geometry rib: E:/MyDocuments/maya/projects/default/rib/_pCube1_pCubeShape1.1.rib
Finished RIB generation E:/MyDocuments/maya/projects/default/rib/cameraShape1.0001.rib
[Liquid] Finished creating RIB
[Liquid]
[Liquid][ Rendering hero pass...
!] Rendering hero pass...
[Liquid] this is elvishray.
Scene E:\liquid\2.3.3\test\test_er_shader\er_shader_lambert.ma completed.