Thanks for trying out both of those sites! I'm sorry they're not working out for you. I know how important it is to have access to the admin site so I will be more than happy to provide you with as much detail as I have available.
First and foremost the computer you're using must be connected to the internet connection the 890L provides. If you're connected to anything else (Wi-fi, dsl, cable, etc) it won't take you to the appropriate page.
The sites you used (http://192.168.1.1 and http://vz.hotspot are both accurate. The 890L suggests Internet Explorer 7.0 , Mozilla Firefox 3.0 , Opera 10.0 , Safari 4.0 , or Chrome 5.0 .