I'll start a new thread, but I felt I should update here first.
After a month tech support finally determined the dvr was faulty and offered a replacement or store credit. So if your Zmodo dvr is freezing on you, you probably have a defective dvr.
More specifically, the dvr I have is an 8-channel, model H8108UV. In order to view any footage I had to go to Internet options in Internet Explorer and deselect "enable protected mode." Not a good idea if I want to surf safely by the way. My dvr is hooked up by cat5e cable to the router. When viewing, remotely and at home, the dvr would freeze, usually in less than five minutes. About once a week the dvr would last up to one hour before freezing. This was "a hard freeze," as the tech support people described, so had to shut off the power and push a menu button and arrows on the dvr to get things working. Sometimes all I had to do was shut the power off, then on. Still, not good for the dvr since it is a computer with a hard drive.
I spoke with tech support multiple times. Rather than going through the ineptitude I observed there, just remember that if your dvr is freezing, you probably have a bad dvr.