Crash on Worldsave -> Mono

What steps will reproduce the problem?
1. Run Mono-HardFloat on Raspberry Pi
2. Simply compile RunUO with gmcs
3. Run Mono and wait till worldsave -> crash
4. Result:
RunUO - [www.runuo.com] Version 2.2, Build 4870.18636
Core: Running on .NET Framework Version 2.0.50727
Core: Running with arguments: -debug
Core: Unix environment detected
Scripts: Compiling C# scripts...done (cached)
Scripts: Skipping VB.NET Scripts...done (use -vb to enable)
Scripts: Verifying...done (2924 items, 742 mobiles) (8.18 seconds)
Regions: Loading...done
World: Loading...done (0 items, 0 mobiles) (0.12 seconds)
ServerList: Auto-detecting public IP address...done ()
This server has no accounts.
Do you want to create the owner account now? (y/n)
Username:
Password:
Account created.
Listening: 127.0.0.1:2593
Listening:xxx.xxx.xxx.xxx:2593
Core: Using standard save strategy
World: Saving...Error:
System.NullReferenceException: Object reference not set to an instance of an 
object
  at Server.BinaryFileWriter.Write (Double value) [0x00000] in <filename unknown>:0
  at Server.Mobiles.BaseCreature.Serialize (Server.GenericWriter writer) [0x00000] in <filename unknown>:0
  at Server.Engines.MLQuests.Definitions.Aurelia.Serialize (Server.GenericWriter writer) [0x00000] in <filename unknown>:0
  at Server.StandardSaveStrategy.SaveMobiles (Server.SaveMetrics metrics) [0x00000] in <filename unknown>:0
  at Server.StandardSaveStrategy.Save (Server.SaveMetrics metrics, Boolean permitBackgroundWrite) [0x00000] in <filename unknown>:0
  at Server.World.Save (Boolean message, Boolean permitBackgroundWrite) [0x00000] in <filename unknown>:0
  at Server.Misc.AutoSave.Save (Boolean permitBackgroundWrite) [0x00000] in <filename unknown>:0
  at Server.Misc.AutoSave.OnTick () [0x00000] in <filename unknown>:0
  at Server.Timer.Slice () [0x00000] in <filename unknown>:0
  at Server.Core.Main (System.String[] args) [0x00000] in <filename unknown>:0
Crash: Generating report...done
Terminated

What is the expected output? What do you see instead?

Expected is a world save, I get a crash. The files of the mobile save are 
created but not more files.

What version of the product are you using? On what operating system?

Latest SVN 1057; Mono with hardflot but same error with softfloat (standard 
debain repo)

Please provide any additional information below.
Raspberry Pi; Already posted here on the first page: 
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=34&t=37174
Original issue reported on code.google.com by fallenwa...@gmx.de on 2 May 2013 at 4:01
esimed / runuo

Crash on Worldsave -> Mono #3
