Please note that in order to get version 4.4.0 to work with Oracle, you must make minor changes to a function and recompile the DotNetNuke solution. You must do this BEFORE attempting to get the site up and running using Oracle.
Pre-requisites:
a) Source version of DotNetNuke 4.04.00
b) Visual Studio 2005
Change Procedure
a) Unzip your DotNetNuke source into a folder on your machine and set up the permissions, virtual folders in IIS.
b) Open the DotNetNuke.sln file under your unzipped folder using Visual Studio 2005.
c) Expand the Folders under DotNetNuke.Library/Components/Security/Permissions like shown below.

d) Double click on the TabPermissionController.vb file under the Permissions folder to open the file.
e)
Browse to FillTabPermissionInfo function (line 117). Function should look like the one shown below.
f)
Change the DirectCast on every line to CType like shown below. Save your changes and recompile.