Just wanted to add that I'm running PostgresQL 8.1, and just fixed the driver jar file (as related to a different topic in this forum), but this problem still exists. When I click on the edit glyph for an HTML file, I get an upload dialog.
What is the CMS showing for the mime-type?
(Last night, my attempts to create a file lead to the CMSAdmin portlet disappearing from the page. This morning, it is working as before again, so that I am able to answer your question).
When I use CMSAdmin to look at /default, I see the list of files. When I click on index.html, it lists the file and shows a type of text/html.
In the directory I created, /Pilates, I created an index.html using the html editor window. When I click on that directory, I see the file. But, when I click on index.html, it gives me the upload window, so I do not see the file listed as I do in /default, and so the type is not shown.