I have been using DNN for many years- since I decided it didn't make any sense to continue development on my own CMS back in (around) 2001. We still have one client using that system but time has come to convert that last site.
So, here's my rant..
I have big a huge DNN fan since day 1 but have been frustrated almost every time I needed to do installs or upgrades.
I am fairly knowledgeable when it comes to install concepts. I work for the Canadian Federal Government (daytime) supporting a fairly large server farm and have supporting and installing IIS web sites for years. I also am a .Net developer for many years and have created some dnn modules. I am also quite knowledgeable when it comes to SQL Server development and admin.
That being said, I would expect DNN installs and upgrades to be smoother than they are- at least for me.
I have has a few upgrades that went off without a hitch but I am never surprised when things go wrong.
My latest pain is after installing version 7.01.02 on our Arvixe server. This time, after doing the scratch install, I experienced an issue with popup window loading displaying '404 - File or directory not found.The resource you are looking for might have been removed, had its name changed, or is temporarily unavailable.'
Starting from scratch and repeating the install had the same results.
Googling that error shows me that I am not the first to have that problem. That gives me an uncomfortable feeling about this version. After trying a few things suggested by others, but find (like with other versions) you fix one issue and another presents itself til you get to the point where you give up.
So then you start Googling again to try to figure out what lower version to try.

I am about to try a lower version but would welcome any help