Neophyte to ASP.NET and DNN.  I succesfully downloaded 4.8x to my XP based test machine.  Heartened, I decided to load onto my dedicated development machine running Vista Home Premium SP1 following one of the latest books.

After downloading DNN 4.9 and configuring IIS, I ran the DotNetNuke Install Wizard by typing http://localhost/dotnetnuke and received the following Error:

-  HTTP Error 500.19 - Internal Server Error

-  0x800700b7

-  Cannot add duplicate collection entry of type 'add' with unique key attribute 'value' set to 'Default.aspx'.

3 things:  a)  when configuring IIS Manager out of the control panel, under the Default Document, I couldn't "make sure that default.aspx" was in the Default Document list with this error:  Cannot add duplicate collection entry of type 'add' with unique key attribute 'value' set to 'Default.aspx'.

b) when I dug around since 4am this morning I did find a MSFT page with the 0x800700b7 number and it instructed to remove a line of code in the config file regarding Default.aspx, which after backing up the original config file, I did and then ran into successive errors and got out of the rabbit hole and restored the config file to the original. 

c)  I've loaded and reloaded and reloaded but am getting nowhere beyond the error.

Any help would be greatly appreciated.  Thanks, ipcalifornia

Hi, thankyou.  I believe its an IIS issue as well.  I loaded and reloaded ASP.net and nothing in the controls indicate that there is a problem.

After three days I haven't reached http://localhost.  After many hours of searching and tinkering, I believe it is an IIS 7.0 issue.  I stopped looking when GOOGLE returned our conversation here as the No. 2 result of a long query and not much else was close.  Admittedly, I've learned alot, but I just want to load DNN.

From what I've read, where the user's CPU runs Windows Vista Premium, the only viable path to DNN requires upgrade to MS Server 2008. There are two articles on this method, and one indicates that MS Srver Express is unable to reliably run DNN.  Am I missing the forest for the trees?  Does it sound like a reasonable proposition that Windows Vista Home Premium can not support DNN sufficiently without upgrading to full Windows 2008 Server?

These are two version of articles.  I initially tried to configure and load from a Wrox book by Sean Walker. 

http://sunsethillsolutions.com/Resources/DotNetNuke/tabid/362/articleType/ArticleView/articleId/16/Default.aspx

http://www.adefwebserver.com/DotNetNukeHELP/DNN4_DevelopmentEnvironment/DNN4DevelopmentEnvironment1.htm

My only thought is to unload MS Server X, MS SQL X, MS VWD X, and everything else it took me 8 hours to download and install. After 3 days and the prospect of another 10 hours of loading, I'm trying not to think about my PHP and MySQL solution which can be up in an hour.  If you have any place to direct me, I'd greatly appreciate it.

Yep - you were right - it's fixed and WORKING!!!  Thank you.