I guess im not used to CMS's  -  I naively expected a CMS would have a  kind of local environment where you made all your fundamental changes then published stuff to the web when you were ready - instead everything is handled on the web which means everything you do is kind of Live so if you screw something up (as I managed to do importing a NEW Skin) the site comes tumbling down.

Ah -- that explains a lot.  You were thinking of static websites and the associated tools that "deployed" sites/updates (hello, FrontPage).   With frameworks like DNN (it's really a framework, not a CMS as it lacks even basic content revisioning, but that's another topic...) you have to envision your sites as being dynamic.  Even if you're not providing user accounts you still have visitors accessing content which alters the database in terms of UsersOnline, site log history, LinkClick counters, etc.  Even if visible content remains the same, under the covers the site is an ever-evolving entity rather than just static files.  Thanks to this you end up with a vastly more powerful web platform but also something that's a lot more complicated to properly administrate.

As already mentioned, you should maintain a local "development" copy of your site to test new modules/skins on.  Doing so will save your "live" site from most incompatability disasters.  Also, if you're not already doing so, you'll want to make backup copies of your "live" site (both files and database) to have something to fall back on if and when a disaster does occur.

<p>Thanks for your comments -&#160;that &#160;makes&#160;things&#160; a bit clearer</p>