I have the blog and a few text/html modules throughout the site and they are working absolutely fine.

I've been wracking my brains over the issue - I am at a complete loss as I'm not really sure how to trouble shoot it.

I am using version 4 of DotNetNuke (downloaded a couple of days ago)

Notes:
1) I have installed the 3rd party "Advanced Datagrid" module
2) I can get text into the Announcements RTE if I tab to it. The background still stays grey and no mouse actions are allowed
3) With regard to the file system, if I look in the DesktopModules/Announcements folder I have two .txt files (not sure what these are for)

Text file (04.00.00.txt) has text pertaining to "Announcements_03.04.00_Install.resources"
Text file (04.00.01.txt) has text pertaining to "Announcements_04.00.00_Install.resources"

I'm not sure whether this would have anything to do with it. I'm no rocket scientist but they look like installation logs so I'm not sure why there are two versions.

This couldn't be somekind of freaky permissions thing could it?

Cheers,

Problem solved. It was entirely self inflicted.

I had set up a custom skin, tested with a couple of HTML/TEXT Modules etc - everything worked fine.

THEN

I changed the admin skin to my custom skin and set up the Announcements module. At this point I hit the RTE problems. 

I thought this was specific to the Announcements module but of course, something in my skin had messed up all of the RTE editors. If I had been thorough and checked then I would have found this to be the case.

Not sure entirely what the difference is in my custom skin, I ended copying the MminimalEntropy admin skin and adjusting that instead.

Problem solved - I feel like an idiot but at least I found the cause.

Cheers,