Thank you all for the suggestions. It did end up being a Windows server directory permissions problem, I failed to add one user to the DNN directory in the new instance. The new 9.1.1 instance and the upgraded instance are both working properly. The upgraded instance is running 9.6.0 RC1 and I will use it for testing the version.
Thanks again and special thanks to @ Joe Craig for prompting me to look closer at permissions.
One piece of advise to all who plan on upgrading....
First, make a backup of your current versions database and directory. MAKE SURE you upgrade all modules, skins, themes, containers, extensions and .NET Framework PRIOR to upgrading a site.