how to fix this strange error regarding NHibernate inside Unity?

Hi all,

I am trying to setup a Unity app to connect to a MySQL database via NHibernate. I added to the Assets/Libs the following DLLs, taken both from the official NHibernate 3.0 binaries and the Mono runtime GAC repository:

• Antlr3.Runtime
• Castle.Core
• Iesi.Collections
• log4net
• mysql.data
• NHibernate
• NHibernate.ByteCode.Castle
• Remotion.Data.Linq
• System.Configuration
• System.Data
• System.Data.DataSetExtensions
• System.Xml
• System.Xml.Linq
• an assembly with data objects suitable for NHibernate

I changed, in Player Settings, the API compatibility level from ".NET 2.0 Subset" to ".NET 2.0" to allow the project to use all assemblies referenced internally by the NHibernate dlls.

I use the following code at the beginning of the Start method of a C# script attached to the main camera of the scene:

// Configuring Log4Net XmlConfigurator.Configure(new FileInfo(@"log4net.config"));

     // NHibernate
     if (Log.IsDebugEnabled) {
         Log.DebugFormat("BaseDirectory[{0}] RelativeSearchPath[{1}]", AppDomain.CurrentDomain.BaseDirectory, AppDomain.CurrentDomain.RelativeSearchPath);
     }
     var cfg = new NHibernate.Cfg.Configuration();
     cfg.Configure();
     cfg.AddAssembly(typeof (User).Assembly);
     sessionFactory = cfg.BuildSessionFactory();

     var schema = new SchemaExport(cfg);
     schema.Create(true, false);

I have the log4net.config and the hibernate.cfg.xml in the root directory of the project, where they are visible and supposedly local for both the generated executable that is deployed there and the Unity3D IDE. But when starting my app, i get a strange error:

ArgumentNullException: Argument cannot be null.

(Filename: Assets/Main.cs Line: 36)

The problem lies in the following function inside the class NHibernate.LoggerProvider:

private static string GetNhibernateLoggerClass() { var nhibernateLogger = ConfigurationManager.AppSettings.Keys.Cast<string>().FirstOrDefault(k => NhibernateLoggerConfKey.Equals(k.ToLowerInvariant())); string nhibernateLoggerClass = null; if (string.IsNullOrEmpty(nhibernateLogger)) { // look for log4net.dll string baseDir = AppDomain.CurrentDomain.BaseDirectory; string relativeSearchPath = AppDomain.CurrentDomain.RelativeSearchPath; string binPath = relativeSearchPath == null ? baseDir : Path.Combine(baseDir, relativeSearchPath); var log4NetDllPath = Path.Combine(binPath, "log4net.dll");

             if (File.Exists(log4NetDllPath))
             {
                 nhibernateLoggerClass = typeof (Log4NetLoggerFactory).AssemblyQualifiedName;
             }
         }
         else
         {
             nhibernateLoggerClass = ConfigurationManager.AppSettings[nhibernateLogger];
         }
         return nhibernateLoggerClass;
     }

That ends returning null because both AppDomain.CurrentDomain.BaseDirectory and AppDomain.CurrentDomain.RelativeSearchPath are null probably. So after a day of research im stuck with this issue. Is there any possible workaround?

Thanks in advance.