Thanks to everyone who posted, using the info I was able to track down the problem.  I'll give a brief explanation here so that others who run into this will know what to do to correct the issue. 

I thought that .NET4 was fully installed under IIS since when I went to create an App Pool for my install of DNN I would get version 4.x as a choice of framework to use.  But apparently the updates, etc. from MS that have been applied to my computer did not fully integrate .NET4 into IIS as when I would get to the point of converting my DNN target directory to an application in IIS I would see only choices of default app pool, classic .net app pool, and the app pools that I created.

I used Mark's advice and ran the command to install .NET4 to IIS after which when I went to convert my DNN directory to an application I had the additional options of ASP.NET v4.0, ASP.NET v4.0 classic.  I would still select the app pool I specifically created for this install that I had previously setup but these two new options told me that things were in better shape.

After I installed the .NET4 to IIS, I just did a fresh install of DNN7, even creating a new app pool using the 4.x .NET framework option making sure to have the Integrated Pipeline option selected.  This time around the install went just fine without errors.  

Ira