Entity Framework 'add/update' error on server only - visual-studio-2010

Question

I'm running into a problem that only seems to affect an application when its been deployed.
Here are the details:
- Application developed in Visual Studio 2010, using MVC 4 (using Razor) and Entity Framework
- Application is going against a database running Oracle 11g
- We've got some developers using XP and others using Win7.
- The application was bin-deployed to a server running WindowsServer 2008
The application has the following functionality:
try
{
COMMENT_TABLE comment = new COMMENT_TABLE();
comment.comment_id = id_val;
comment.comment_text = fc["txtcomments"];
db.COMMENT_TABLE.Add(comment);
db.SaveChanges();
return RedirectToAction("Det", new { id = evalid });
}
catch (Exception ex)
{
return Content(ex.Message);
}
In our development environment under Visual Studio, this works perfectly. However, when we deploy it to our web server, we get the following error:
"An error occurred while updating the entries. See the inner exception for details".
However, other parts of our code (where we do searches and retrieve records, or where records are updated) have no problem, so at least some database access works. Its just when we try to do the above update that the error occurs.
I found a couple of references, to this, but they all seem to be dealing with retrieving the error through Visual Studio (which, of course, doesn't help because it works in development.)
Any idea what the issue could be?

Answer 1

Ok, my apologies... I think I found the problem.
I had some problems getting the inner exception working (didn't realize I had to call 'GetBaseException'), but once I did I noticed something...
The 'comment_text' field was set to non-null in the database... in another part of the code, the comment text was getting populated by user.identity.name (i.e. the person logged in).
In Visual Studio, user.identity.name was set to the user login. However, on the web server it was null. So, the field wasn't set properly.
Now I feel a bit foolish. Sorry to have wasted everyone's time.