System.SystemException: Error running gmcs: Cannot find the specified file
  at Mono.CSharp.CSharpCodeCompiler.CompileFromFileBatch (System.CodeDom.Compiler.CompilerParameters options, System.String[] fileNames) [0x00000] in <filename unknown>:0
  at Mono.CSharp.CSharpCodeCompiler.CompileAssemblyFromFileBatch (System.CodeDom.Compiler.CompilerParameters options, System.String[] fileNames) [0x00000] in <filename unknown>:0
  at Mono.CSharp.CSharpCodeCompiler.CompileAssemblyFromFile (System.CodeDom.Compiler.CompilerParameters options, System.String fileName) [0x00000] in <filename unknown>:0
  at System.Xml.Serialization.XmlSerializer.GenerateSerializers (System.Xml.Serialization.GenerationBatch batch, System.CodeDom.Compiler.CompilerParameters cp) [0x00000] in <filename unknown>:0
  at System.Xml.Serialization.XmlSerializer.RunSerializerGeneration (System.Object obj) [0x00000] in <filename unknown>:0
[registered] /permissions (Rocket.Unturned.Commands.CommandP/permissions)
[registered] /rocket (Rocket.Unturned.Commands.CommandRocket/rocket)
[registered] /tp (Rocket.Unturned.Commands.CommandTp/tp)
[registered] /tphere (Rocket.Unturned.Commands.CommandTphere/tphere)
[registered] /unadmin (Rocket.Unturned.Commands.CommandUnadmin/unadmin)
[registered] /v (Rocket.Unturned.Commands.CommandV/v)
[registered] /vanish (Rocket.Unturned.Commands.CommandVanish/vanish)
This server will automatically save every 1800 seconds
General: Current backend date: 01/01/1970 00:00:50
General: Halloween: [10/27/2018 00:00:01, 11/01/2018 23:59:59]
General: Christmas: [12/10/2018 00:00:01, 12/31/2018 23:59:59]
Bad thread localStacktrace:


Native stacktrace:

        mono() [0x49ff2f]
        mono() [0x4f390e]
        mono() [0x426c19]
        /lib/x86_64-linux-gnu/libpthread.so.0(+0x11390) [0x7f57b976b390]
        mono() [0x5f2297]
        mono() [0x5f3dd0]
        mono() [0x5f720b]
        mono() [0x5e91c5]
        mono() [0x5ea28e]
        mono() [0x5ea6cc]
        mono() [0x5ecb49]
        mono() [0x5ed138]
        mono(mono_domain_finalize+0x64) [0x5a60f4]
        mono() [0x4243bb]
        mono(mono_main+0x1024) [0x476814]
        /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0) [0x7f57b93b0830]
        mono(_start+0x29) [0x422e79]

Debug info from gdb:


=================================================================
Got a SIGSEGV while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================

./start.sh: line 43: 13063 Aborted                 mono RocketLauncher.exe $INSTANCE_NAME