EDIT: I retried booting later and still cannot play unfortunately. I am unsure as to what made it work before, and I checked the folder for an error log, but there was no log there.
I was booting the game to test before I gave the error log and it now works for some unknown reason!!! Thanks so much for your time and effort though, it is really appreciated! 
Tried reinstalling the game, did not work when i tried to play it again, tried using a different graphics card, still the same issue.
I deleted the local data, and reinstalled the game, but it did not work still 
I start steam as admin. And by Write-Access do you mean whether or not the Read-Only box is ticked in the properties of steam? If so the box is not checked.
QuoteAs you exception says, "AssetNotFoundException", means that the assets you listed are not found by the program. Look manually if they exists in you steam gamefolder, if they are there delete them and try to repair the game again. If that all don't work for your problem i think you should reinstall complete game.
I did that and repaired the game again, then tried reinstalling as that did not work, however it still does not work.
I did that, but there was no message regarding loading damaged data, it was 100% successful. Have I done something wrong?
Yes there is, I assume it is useful so here it is:
/////////////////////////////////////////////////////////////////////////////////
Report of 20.12.2014 by Angus
OS: Windows 8.1 (x64) Version: 6.3 Java version: 1.8.0_25 JVM architecture: amd64
CPU cores: 4 Executor poolsize: 0
Memory used: 22.08 MB reserved: 113.57 MB max: 2087.45 MB
/////////////////////////////////////////////////////////////////////////////////
Existing buffers: 164
(b: 64 f: 69 i: 1 s: 30 d: 0)
Total heap memory held: 21560kb
Total direct memory held: 4562kb
(b: 4514kb f: 42kb i: 0kb s: 6kb d: 0kb)
/////////////////////////////////////////////////////////////////////////////////
Settings:
Resolution: 1280x720 (Windowed)
Frequency: 60 Vsync: off
DepthBits: 16
BitsPerPixel: 24
Samples: 1
MaxFrames: 200
Renderer: LWJGL-OpenGL2
Anisotropic: 0
DynamicLights: 100 Quality: 2
ViewDistance: 9 (LOD: 25)
LS(Q)/LG/ENV/PHD/NM/FOD/FXAA/SPEC/REFR/SSAO: 1(50)/1/1/1/1/1/0/0/11
/////////////////////////////////////////////////////////////////////////////////
Graphics: GeForce GTS 450/PCIe/SSE2 Vendor: NVIDIA Corporation OpenGL version: 4.4.0
Accelerated Memory: Indeterminate
GLMaxTextureSize: 16384
GLMaxTextureImageUnits: 32
GLMaxArrayTextureLayers: 35071
GLMaxVertexTextureImageUnits: 32
GLMaxVertexUniforms: 4096
GLMaxFragmentUniforms: 2048
GLMaxVaryingFloats: 124
GLMaxVertexAttribs: 16
Capabilities: [FrameBuffer, FrameBufferMRT, FrameBufferMultisample, TextureMultisample, OpenGL20, OpenGL21, OpenGL30, OpenGL31, OpenGL32, ARBprogram, GLSL100, GLSL110, GLSL120, GLSL130, GLSL140, GLSL150, VertexTextureFetch, TextureArray, TextureBuffer, FloatTexture, FloatColorBuffer, FloatDepthBuffer, PackedFloatTexture, SharedExponentTexture, PackedFloatColorBuffer, TextureCompressionLATC, NonPowerOfTwoTextures, MeshInstancing, VertexBufferArray, Multisample, PackedDepthStencilBuffer]
/////////////////////////////////////////////////////////////////////////////////
Camera location: (0.0, 0.0, 0.0) Camera rotation: (0.0, 0.0, 0.0, 1.0)
Total running time: 1.9355872
/////////////////////////////////////////////////////////////////////////////////
/C:/Program Files (x86)/Steam/SteamApps/common/RisingWorld/risingworld.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-core.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-desktop.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-effects.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-jbullet.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jinput.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jbullet.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-jogg.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-lwjgl.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-lwjgl-natives.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-networking.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-plugins.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/jME3-terrain.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/j-ogg-oggd.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/j-ogg-vorbisd.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/lwjgl.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/stack-alloc.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/core/vecmath.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/jiw/jiw-gui.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/jiw/jiw-bytenetwork.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/server.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/commons.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/lib/sqlite-jdbc.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/lib/luaj.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/assets/interface.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/assets/materials.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/assets/models.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/assets/music.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/assets/sounds.jar Checksum: N/A
/C:/Program Files (x86)/Steam/steamapps/common/RisingWorld/data/assets/textures.jar Checksum: N/A
/////////////////////////////////////////////////////////////////////////////////
Error details:
com.jme3.asset.AssetNotFoundException: MatDefs/VoxelTerrain/VoxelTerrain.j3md
com.jme3.asset.DesktopAssetManager.loadAsset(DesktopAssetManager.java:283)
com.jme3.material.Material.<init>(Material.java:120)
content.Materials.initVoxelMaterial(SourceFile:546)
content.Materials.initialize(SourceFile:160)
content.Game.initMaterials(SourceFile:1378)
q.g.update(SourceFile:59)
com.jme3.app.state.AppStateManager.update(AppStateManager.java:287)
commons.JIWApplication.update(SourceFile:66)
com.jme3.system.lwjgl.LwjglAbstractDisplay.runLoop(LwjglAbstractDisplay.java:151)
com.jme3.system.lwjgl.LwjglDisplay.runLoop(LwjglDisplay.java:185)
com.jme3.system.lwjgl.LwjglAbstractDisplay.run(LwjglAbstractDisplay.java:228)
java.lang.Thread.run(Unknown Source)
Whenever I launch the game I just get stuck in this screen and nothing happens.
