OK think I have found it now.

Found the zip files within the original zip file I downloaded, so copied them to my webserver and ran "http://www.mydomain.com/dnn/Install/Install.aspx?mode=InstallResources".

Text/HTML now appears.

I am having the same problem, where the Text/Html modules are not showing on any page. I currently run DNN 4.0.2 and installed Text/Html 4.0.8 module and kept getting errors, I had to remove the module and installed the original 4.0.2 Text.Html module from the original zip file. 

I kept getting errors loading the site and found a blog that said to try deleing the DotNetNuke.Modules.Html.dll and DotNetNuke.Modules.Html.SqlDataProvider.dll files. I tried that and the site loads now but none of the HTML modules show on any page again.

Any suggestions?

Thanks.