Given the name names of the tables that hold the repository/wiki are not really hidden, they have the word Repository in the them, and the names of the tables for the Wiki have the name Wiki in them, and all the FILE for the repository are in a folder set inside your portal/0/ folder,  your host could have maybe put a little bit more effort , than none at all into helping you too.

Westa

The OP's hosting company is probably (more) specialized in working with (L/W)AMP-setups, just like others are with IIS/MSSQL/ASP.NET.

And, for your information, Joomla is just stating that they made their CMS for Apache/MySQL, just like DNN is made for IIS/MSSQL. It is therefore pretty fair to me, that they will officially not support other custom setups; if people want to try to run Joomla in IIS and/or MSSQL, that is completely up to them and they will probably get some unofficial support, out of shared interests. The exact same goes for DNN, who will most probably not (officially) support people running DNN in custom non-Microsoft environments.

Also, sidenote to that: Joomla can be easily made to run within IIS (PHP is pretty portable), where DNN will need a heavily customized Apache-environment (including using the Mono-project for Apache) to run in it, since Microsoft doesn't want it's .NET to be used within other environments than their own. Therefore people will tend to run Joomla on an MS-environment far easyer then DNN on a non-MS environment, so it's logical that Joomla makes note of not supporting those setups.