I have the same problem and i can't fix it :
[16:59:13.501] Activate interlocks!
[16:59:14.233] Dynatherms connected!
[16:59:14.235] Infracells up!
[16:59:15.073] Instance root changed to: C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances
[16:59:15.076] No MD5 for ConfigFile: /options.txt
[16:59:15.088] Selection changed to: WesterosCraft-1.11.2
[16:59:17.424] Megathrusters are go!
[16:59:27.486] No MD5 for ConfigFile: /options.txt
[16:59:27.494] Selection changed to: WesterosCraft-1.11.2
[16:59:29.142] Launch args:
[16:59:29.143] =======================
[16:59:29.144] C:\Program Files (x86)\Java\jre1.8.0_172\bin\javaw.exe
[16:59:29.145] -Xms3G
[16:59:29.145] -Xmx3G
[16:59:29.146] -XX:+UseG1GC
[16:59:29.146] -XX:+AggressiveOpts
[16:59:29.147] -Djava.library.path=C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\natives
[16:59:29.148] -Dfml.ignorePatchDiscrepancies=true
[16:59:29.148] -Dfml.ignoreInvalidMinecraftCertificates=true
[16:59:29.149] -cp
[16:59:29.149] C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\forge.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\launchwrapper.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\asm.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-lib.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-compiler.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-actors-migration.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-continuations-library.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-continuations-plugin.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-parser-combinators.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-reflect.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-swing.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\scala-xml.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\akka-actor.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\typesafe-config.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\lzma.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\trove4j.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\vecmath.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\jopt-simple.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\MercuriusUpdater.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\netty-1.6.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\oshi-core-1.1.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\jna-3.4.0.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\platform-3.4.0.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\icu4j-core-mojang-51.2.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\jopt-simple-4.6.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\codecjorbis-20101023.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\codecwav-20101023.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\libraryjavasound-20101123.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\librarylwjglopenal-20100824.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\soundsystem-20120107.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\netty-all-4.0.23.Final.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\guava-17.0.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\commons-lang3-3.3.2.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\commons-io-2.4.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\commons-codec-1.9.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\jinput-2.0.5.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\jutils-1.0.0.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\gson-2.2.4.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\authlib-1.5.24.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\realms-1.10.16.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\commons-compress-1.8.1.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\httpclient-4.3.3.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\commons-logging-1.1.3.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\httpcore-4.3.2.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\fastutil-7.0.12_mojang.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\log4j-api-2.0-beta9.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\log4j-core-2.0-beta9.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\lwjgl-2.9.4-nightly-20150209.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\lib\lwjgl_util-2.9.4-nightly-20150209.jar;C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\bin\minecraft.jar
[16:59:29.150] net.minecraft.launchwrapper.Launch
[16:59:29.151] --username
[16:59:29.151] Pireaspi
[16:59:29.152] --version
[16:59:29.153] 1.11.2
[16:59:29.153] --gameDir
[16:59:29.154] C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2
[16:59:29.155] --assetsDir
[16:59:29.155] C:\Users\Maxou\AppData\Roaming\WesterosCraft\assets
[16:59:29.156] --assetIndex
[16:59:29.157] 1.11
[16:59:29.157] --uuid
[16:59:29.158] f8e5c698a82e47b4a70812ea35c0495b
[16:59:29.158] --accessToken
[16:59:29.159] 259d7e31ddcd4581ac4045a35afc7b96
[16:59:29.159] --userType
[16:59:29.160] MOJANG
[16:59:29.160] --versionType
[16:59:29.161] ${version_type}
[16:59:29.161] --fullscreen
[16:59:29.162] --server
[16:59:29.162] mc.westeroscraft.com
[16:59:29.163] --resourcePackDir
[16:59:29.163] C:\Users\Maxou\AppData\Roaming\WesterosCraft\instances\WesterosCraft-1.11.2\resourcepacks
[16:59:29.164] --tweakClass
[16:59:29.165] net.minecraftforge.fml.common.launcher.FMLTweaker
[16:59:29.165] =======================
Error occurred during initialization of VM
Could not reserve enough space for 3145728KB object heap
[16:59:29.249] Minecraft process terminated
