OK, this 'junk' is part of DotNetNuke. It is a way of storing data to be used by javascript code. If you look at the page source for DotNetNuke.com for any page you'll see it there, just search the html for "__dnnVariable". Now what the actual data is, from the looks of the one on DotNetNuke.com, is.... the main menu (So no wonder it has refences to every page in the portal). When a page is loaded some JS code take this data and renders the Main menu... which is really really stupid because it means there is no main menu if the end user has javascript disabled and search engines have no way to navigate any DotNetNuke website and therefore needs to be fixed very soon.So the reason why your not geting very good results in search engines is because some idiot wrote the code for the main menu.
Search engines ignore input fields (especially hidden ones) so you would have no worries with it affecting search results, so if this is appearing in word density tools then I would not use that tool again as was obviously written by someone who doesn't have a clue what he's doing and I would probably avoid the website that you found it too as it probably contains a lot of misinformation.
OH, by the way alexa.com tells me that your only good keyword is 'childminding', your getting most of your search results from this. http://www.alexa.com/siteinfo/heavensenthelp.com.au
In fact your first on google.com.au for that keyword http://www.google.com.au/search?q=childminding
So.. yeah... just go turn off Javascript in your browser and visit your site and cry at the fact that you can't navigate it, as well as search engine crawlers not being able to navigate it all becouse some idiot wrote the code for the main menu.
BTW - anyone know how to report this stupidity as a bug? or design flaw? or whatever it should be called? Maybe, I'll just post it on thedailywtf.com for it's entertainment value?