Update yours .NET Framework
"sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enable CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please enable the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=155569 for more information."
and no idea whether this is important "Could not load file or assembly 'UnrealEdCSharp, Version=1.0.5507.32888, Culture=neutral, PublicKeyToken=null' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)"