<p>Has anybody been successful in integrating the Enterprise Library v4.0 with SharePoint WSS 3.0?  I created a very simple .ASPX page.  It's only purpose will to be to connect to an Oracle database and display some values in a DropDownList.  But right now, all it does is displays Hello World.  I've added the necessary references and everything compiles fine.  When I test the page, it displays Hello World.  But once I add the using Microsoft.Practices.EnterprisesLibrary.Data, the page no longer works. I just get the standard Unknown Error message.  Is there a log file I can check? </p>

<p>I'm looking for any steps or tips that I can use to get this up and running.  I use this Enterprise Library in all my ASP.NET applications and it works great.  Trying to get this to work in SharePoint seems like a natural fit.  But why does it seem so difficult?  And why does there seem to be a lack of information?</p>

<p>Anyways, thank you so much for any information anybody can provide.</p>

Are you able to debug and see where the failure is occurring in your code?  Is it occurring on an Enterprise Library related call?  If so I would capture the exception that is being thrown and evaluate the message that it provides using; try {} catch (Exception ex) {}.
One thing I have seen with Enterprise Library that if it is not properly configured it will sometimes log messages to the Event Log on the server.
I'm sorry I can't get much more information without more technical details about your implementation.  I can assure you though that Enterprise Library works very well with SharePoint and that for the past few years I have used Enterprise Library in all of my SharePoint solution work.