Deployed project throws Object reference not set

[yAm]

Hello,

We've been trying to deploy a project to a shared hosting service, and
after compiling the latest trunk with partial trust, the following
error appears after the redirect from the Default.aspx. We've mapped
monorail to the .ashx extension. The project itself runs fine on our
local pc's.

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not
set to an instance of an object.

Source Error:
An unhandled exception was generated during the execution of the
current web request. Information regarding the origin and location of
the exception can be identified using the exception stack trace
below.

Stack Trace:
[NullReferenceException: Object reference not set to an instance of an
object.]

Castle.MonoRail.Framework.EngineContextModule.CreateRailsEngineContext(HttpContext
context) in EngineContextModule.cs:363

Castle.MonoRail.Framework.EngineContextModule.OnStartMonoRailRequest(Object
sender, EventArgs e) in EngineContextModule.cs:116

System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
+92
System.Web.HttpApplication.ExecuteStep(IExecutionStep step,
Boolean& completedSynchronously) +64

Could someone help us with this error? Is it a monorail issue or a
setting on the host machine?

[Ben Lovell]

I've had null reference exceptions before when ASP.NET session mode is "Off". Check that for a start?