Ok, I rolled back to 7.0.5
Everything went back to normal. I made sure I unblocked my upgrade package and upgraded again. Everything worked fine it seemed until I disabled the popup from dnn after login. Then I got the same issues with not being able to access any Host pages, and the same urlrewrite error.
Currently I have rolled back to 7.0.5 and thinking I may need to do a clean install. I want to use a bootstrap skin that requires 7.1 or newer dnn version, or else I would leave it alone. But it would be nice to find out what is breaking the rewrite code.

I'm also having this problem.

I did a clean install and installed a custom skin from "Extensive Skin (15 Colors) // Responsive Design // Mobile & Tablet // Slider Banner // DNN 5 & 6 & 7"

It worked pre-DNN 7.2.2, so i want to know what has been changed or fixed since.

This is the error message i'm receiving from the event viewer:

--------------------

HTTP Error Code 404 Page Not Found

TabId:

PortalAlias:domain

OriginalUrl:/undefined?1397568352024

Referer:http://domainname/mailing

Url:http://domainname/undefined?1397568352024

UserAgent:Mozilla/5.0 (Windows NT 6.1; WOW64; rv:28.0) Gecko/20100101 Firefox/28.0

HostAddress: xxx..

HostName: xxx..

Server Name: xxx.

 In my case, the Gravity skin is being used, the original not the Future. Do you think that would have an effect on the url rewrite behaviors?